Hormones are other substances. Hormones are the human engine

It includes organs that produce hormones that are necessary for the normal functioning of the body. Each type of hormone is responsible for a certain, and their insufficient or excessive production affects the performance of all organs and tissues. It is necessary to consider in detail what hormones are and why a person needs them.

Concept and classification

What is a hormone? The scientific definition of this concept is rather complicated, but if explained in a simple way, then these are active substances that are synthesized in the body, necessary for the performance of all organs and systems. When the level of these substances in the body is disturbed, a hormonal failure occurs, which, first of all, affects the nervous system and the psychological state of a person, and only then dysfunctions of other systems begin to occur.

What hormones are can be understood by finding out their functions and significance in the human body. They are classified according to the place of formation, chemical structure and purpose.

According to chemical characteristics, the following groups are distinguished:

• protein-peptide (insulin, glucagon, somatropin, prolactin, calcitonin);
• steroids (cortisol, testosterone, dihydrotestosterone, estradiol);
• amino acid derivatives (serotonin, aldosterone, angiothesin, erythropoietin).

A fourth group can be distinguished - eicosanoids. These substances are produced in non-endocrine organs and act locally. Therefore, they are called "hormone-like" substances.

• thyroid;
• parathyroid gland;
• pituitary;
• hypothalamus;
• adrenal glands;
• ovaries;
• testicles.

Each hormone in the human body has its own purpose. Their biological functions are shown in the following table:

This table only shows the main purposes of several hormones. But each of them can stimulate and be responsible for several functions at once. Here are a few examples: Adrenaline is not only responsible for muscle contraction, but also regulates pressure and in some way participates in carbohydrate metabolism. Estrogen, which stimulates reproductive function, affects blood clotting and lipid metabolism.

The thyroid gland is located in the front of the neck and has a very small weight - about 20 grams. But this small organ plays a big role in the body - it is in it that hormones are produced that stimulate the work of all organs and tissues.

And - the main hormones of this gland. For their formation, iodine is needed, which is why they are called iodine-containing. T3 - contains three iodine molecules. It is produced in small amounts and has the ability to quickly break down, getting into the blood. T4 - consists of four molecules, has a longer pot life and is therefore considered more important. Its content in the body is 90% of all human hormones.

Their functions:

• contribute to the development of proteins;
• stimulate energy metabolism;
• increase blood pressure;
• affect the work of the central nervous system;
• control cardiac performance.

If there is a lack of T3 and T4, then the performance of all body systems is disrupted:

• decreased intelligence;
• metabolism is disturbed;
• decreased production of sex hormones;
• dulled heart sounds.

Serious disorders in the psyche and nervous system can be observed. Elevated levels cause irritability, sudden weight gain or loss, tachycardia, hyperhidrosis.

The two states in which these substances exist are:

• Associated - do not affect the body as long as they are delivered by albumin protein to organs.
• Free - have a biologically active effect on the body.

Since everything is interconnected in the body, these types of hormones are reproduced under the influence of TSH produced in. That is why information is important for diagnosis not only about thyroid hormones, but also about the TSH hormone.

Parathyroid hormones

Behind the thyroid gland is the parathyroid gland, which is responsible for the concentration of calcium in the blood. This is due to - PTH (parathyrin or parathyroid hormone), which stimulates metabolic processes in the body.

Functions of PTH:

• reduces the level of calcium excreted by the kidneys;
• stimulates the absorption of calcium into the blood;
• increases the level of vitamin D3 in the body;
• with a deficiency of calcium and phosphorus in the blood, it removes them from the bone tissue;
• with an excess of phosphorus and calcium in the blood, deposits them in the bones.

A low concentration of parathyroid hormone leads to muscle weakness, problems with intestinal peristalsis, heart failure and a change in the mental state of a person.

Symptoms of a decrease in parathyroid hormone:

• tachycardia;
• convulsions;
• insomnia;
• occasional chills or feeling hot;
• heartache.

A high level of PTH has a negative effect on bone formation, the bones become more brittle.

Symptoms of elevated PTH:

• growth retardation in children;
• muscle pain;
• frequent urination;
• skeletal deformity;
• loss of healthy teeth;
• constant thirst.

The resulting calcification disrupts blood circulation, provokes the formation of stomach and duodenal ulcers, and the deposition of phosphate stones in the kidneys.

The pituitary gland is a brain process that produces a large number of active substances. They are formed in the anterior and posterior part of the pituitary gland and have their own special functions. It also produces several types of hormones.

Formed in the anterior lobe:

• Luteinizing and follicle-stimulating - are responsible for the reproductive system, the maturation of follicles in women and spermatozoa and men.
• Thyrotropic - controls the formation and release of the hormones T3 and T4, as well as phospholipids and nucleotides.
• Somatropin - controls the growth of a person and his physical development.
• Prolactin is the main function: the production of breast milk. It also takes part in the formation of secondary female characteristics and plays an insignificant role in material metabolism.

Synthesized in the posterior lobe:

• - affects the contraction of the uterus and, to a lesser extent, other muscles of the body.
• Vasopressin - activates the work of the kidneys, removes excess sodium from the body, participates in water-salt metabolism.

In the middle lobe - melanotropin, is responsible for the pigmentation of the skin. According to recent data, melanotropin may have an effect on memory.

The hormones produced in the pituitary gland are under the influence of the hypothalamus, which plays the role of a regulator of the secretion of active substances in the organs. is a link connecting the nervous and endocrine systems. The hormones of the hypothalamus - melanostatin, prolactostatin, inhibit the secretion of the pituitary gland. All the rest, for example, luliberin, folliberin, are aimed at stimulating the secretion of the pituitary gland.

The active substances that are formed in the pancreas make up only 1-2% of the total. But, despite the small amount, they play a significant role in digestion and other body processes.

What hormones are produced in the pancreas:

• Glucagon - increases the level of glucose in the blood, is involved in energy metabolism.
• Insulin - reduces the level of glucose, inhibits its synthesis, is a conductor of amino acids and minerals to the cells of the body, prevents protein deficiency.
• Somatostatin - reduces the level of glucagon, slows down blood circulation in the abdominal cavity, prevents the absorption of carbohydrates.
• Pancreatic polypeptide - regulates contractions of the muscles of the gallbladder, controls secreted enzymes and bile.
• Gastrin - creates the necessary level of acidity for the digestion of food.

Violation of the production of hormones by the pancreas, in the first place, leads to diabetes. An abnormal amount of glucagon provokes pancreatic tumors of a malignant nature. With failures in the production of somatostatin and leads to various diseases of the gastrointestinal tract.

Hormones of the adrenal cortex and gonads

The adrenal medulla produces very important hormones - adrenaline and norepinephrine. Adrenaline is formed when stressful situations occur, for example, in shock situations, with fear, severe pain. Why is it needed? When there is resistance to negative factors, that is, it has a protective function.

People also notice that when they receive good news, there is a feeling of inspiration - the excitatory function of norepinephrine is activated. This hormone gives a feeling of confidence, stimulates the nervous system, and regulates blood pressure.

Corticosteroid substances are also produced in the adrenal glands:

• Aldosterone - regulates hemodynamics and water-salt balance in the body, is responsible for the amount of sodium and calcium ions in the blood.
• Corticosterone - participates only in water-salt metabolism.
• Deoxycorticosterone - increases the stamina of the body.
• - Designed to stimulate carbohydrate metabolism.

The reticular zone of the adrenal glands secretes sex hormones - that affect the development of secondary sexual characteristics. The female ones include - androstenedione and, which are responsible for hair growth, the functioning of the sebaceous glands and the formation of libido. Estrogens (estriol, estradiol, estrone) are produced in the ovaries, the reproductive function of the female body is completely envy from them.

In men, they practically do not play a role, since their main hormone is testosterone (formed from DEA) and is produced in the testicles. The second most important male hormone - dehydrotestosterone - is responsible for potency, development of the genital organs and libido. In some cases, in men, it can turn into estrogen, which leads to impaired sexual function. Human sex hormones, wherever they are formed, depend on each other and simultaneously affect the body of men and women.

The human body is a complex system that performs a huge number of operations. Hormones play an important role in the proper organization of the human body. These are catalysts for biochemical processes that are produced by endocrine glands. There are different types of hormones, and each of them performs a specific function.

Classification of hormones

Depending on the chemical structure, these types of hormones are distinguished. The protein-peptide group combines the secrets of such glands as the pituitary gland, hypothalamus, pancreatic and parathyroid hormones. This type also includes calcitonin, which is produced by the thyroid gland. The second group includes derivatives of amino acids (norepinephrine and adrenaline, thyroxine, etc.). There are also steroid types of hormones. They are synthesized mainly in the gonads, as well as the adrenal glands (estrogen, progesterone). Hormones of the first two groups are mainly responsible for metabolic processes in our body. Steroid types of hormones control physical development and the process of reproduction. Depending on the method of signal transmission from the secret to the cells, lipophilic and hydrophilic hormones are distinguished. The former easily penetrate the cell membrane into its nucleus. The latter bind to receptors on the surface of the structural element, while triggering the synthesis of the so-called messenger molecules. It is characteristic that hydrophilic hormones are transported with the blood stream, while lipophilic ones bind to its proteins and are thus transported.

human endocrine system

This is the name of the totality of all glands and organs in the human body, which secrete special biologically active elements - hormones. The endocrine system is responsible for many processes, while ensuring the normal development of the body. It controls chemical reactions, generates energy, affects the psycho-emotional state of a person. The endocrine system includes the thyroid, parathyroid, pancreas, pituitary and pineal glands, adrenal glands, hypothalamus. It also includes organs such as testicles and ovaries. All hormones enter directly into the blood or lymph. Any disturbances in the functioning of the human endocrine system can cause serious diseases (diabetes mellitus, tumor processes, obesity, hyper- and hypothyroidism).
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Tissue hormones, their types and functions

This type of hormones is produced in the tissues of the body and their action is usually local. Sometimes these hormones can enter the bloodstream. Histamine is a substance that plays a large role in the occurrence of allergic reactions. In the active state, it causes vasodilation, increases their permeability. Also, histamine promotes contractions of the muscles of the intestine, can cause spasms in the bronchi. Serotonin has the following effect: the vessels narrow, their permeability decreases. It is also called the hormone of happiness. If its production is normal, a person has a good mood, he feels a surge of strength. Both histamine and serotonin are actively involved in the transmission of impulses to the brain. Kinins are another tissue hormones. Their types and functions are as follows. Nanopeptide, kallidin, T-kinin, bradykinin (reduces blood pressure) - all of them, getting into the blood, cause symptoms of the inflammatory process. These hormones are involved in another category of biologically active tissue secretions - prostaglandins. They act on the smooth muscles of the organs, reduce the secretion of gastric juice. Substances such as kalons control cell division. Another type of tissue hormones is gastrin, secretin.

Thyroid. Types of hormones and their functions

This organ has the shape of a butterfly and is located in the neck (front). Its weight is relatively small - about 20 grams. Regulation of the functions of the sexual (reproductive), digestive systems, metabolic processes, maintaining a normal psycho-emotional state - all this is controlled by thyroid hormones. Their types are as follows. Thyroxine, triiodothyronine are extremely important secrets for human health. In order for them to form, a sufficient intake of iodine is necessary. The action of these hormones is similar, but triiodothyronine is more active. First of all, these substances take part in energy metabolic processes. They also affect the functioning of the heart muscle, intestines, and central nervous system. Also, these types of hormones take part in the development of the whole organism, the maturation of the reproductive system. Calcitonin is responsible for the level of calcium in the blood, and also takes part in water and electrolyte metabolism. Insufficient production leads to rapid human fatigue, lethargy, all metabolic processes slow down. If they are produced in excess, then excessive activity and excitability can be observed.

Analysis of the hormones produced by the thyroid gland

If a person has changes such as weight fluctuations (sudden weight gain or weight loss), problems with sexual desire, cessation of menstruation, developmental delay (psychological) in children, then a blood test for hormones produced by the thyroid gland is mandatory. To pass it, you should prepare in a special way. It is best to limit any physical activity on the eve of the test. It is also worth excluding alcohol, coffee, tobacco (at least a day before). Blood sampling takes place in the morning on an empty stomach. Thyroid hormones can be both in a bound and in a free state. Therefore, in the course of research, the amount of free thyroxine, free triiodothyronine, thyrotropin, as well as the level of antibodies to thyroid peroxidase, thyroglobulin, are determined. As a rule, the study takes one day. Depending on the results obtained, we can talk about a particular disease.

and her secrets

On the back surface of the thyroid gland are small glands, which are also called parathyroid glands. They are directly involved in the exchange of calcium and phosphorus in the body. Depending on the characteristics of a person, the gland can be of a mesh type, alveolar or in the form of a continuous mass. It synthesizes parathyroid hormone, which, like calcitonin, takes part in calcium metabolism. It also affects the skeletal system, intestines, kidneys. If the production of parathyroid hormone is impaired, then mental disorders, bone problems, calcification of internal organs and blood vessels are possible. With hypoparateriosis, muscle cramps appear, the heart rate quickens, and headaches may occur. If these signs are present, a blood test for parathyroid hormones may be needed. Their high content increases the level of calcium in the blood, and as a result, causes fragility of bone tissue.

Hormones produced by the adrenal glands

The adrenal glands are paired organs located at the top of the kidneys. These types of hormones and their functions are as follows. The cortical layer of the glands produces substances that regulate the exchange of nutrients and minerals. Also, hormones of this type control glucose levels. The adrenal medulla synthesizes adrenaline and norepinephrine. Often they are developed during strong emotional outbursts (fear, danger). When these hormones enter the bloodstream, blood pressure rises, the heart rate quickens, and the excitability of the receptors of the organs of vision and hearing increases. Thus, the body prepares for the need to endure a stressful situation. The adrenal glands produce glucocorticoid hormones (cortisol) that regulate carbohydrate metabolism. Their concentration depends on the time of day: the maximum amount of cortisol is observed at about 6 o'clock in the morning. Mineralocorticoid hormones (aldosterone) regulate salt metabolism. Thanks to them, fluid is retained in the body. The adrenal glands also secrete androgens such as androstenedione, dehydroepiandrosterone (DEA). They regulate the work of the sebaceous glands, form a libido. In a blood test for adrenal hormones, the level of DEA is examined. Its high content may indicate the presence of tumors of the glands. In addition, an excess of this hormone leads to serious consequences during pregnancy (miscarriage, malnutrition of the child, problems with the placenta). If there are complaints of increased hair growth, earlier puberty, menstrual irregularities, muscle weakness, a blood test for cortisol may be needed.

Pancreas. Types of hormones and their functions

In addition to taking an active part in the processes of digestion, it also produces hormones that are essential for the normal functioning of the body. All of them enter directly into the human blood. This body produces such types of hormones: insulin, c-peptide, glucagon. The main function of insulin is to regulate blood sugar levels. If the processes of its synthesis are disturbed, the development of diabetes mellitus is possible. Insulin also affects the production of active substances in the gastrointestinal tract, the synthesis of estrogens. It can be found in the body in free and bound form. If the amount of insulin is insufficient, then the process of converting glucose into fat and glycogen is disturbed. At the same time, toxins (for example, acetone) can accumulate in the body. Glucagon is also an essential element for our body. It activates the process of splitting fats, increases the level of glucose in the blood. It also reduces the level of calcium, phosphorus in the blood. Types of action of pancreatic hormones are closely interrelated. Thanks to their combined influence, an optimal glucose level is ensured.

Functions of pituitary hormones

The pituitary gland is an endocrine gland, which consists of the anterior and posterior lobes, as well as a small area between them. This organ weighs only 0.5 grams, but it performs quite important functions. The pituitary gland synthesizes the following types of human hormones. Adrenocorticotropic hormone stimulates the adrenal cortex. It also affects the formation of melanin. affects the proper functioning of the reproductive system. Thanks to him, ovulation is stimulated, androgens are produced. Thyrotropic hormone coordinates the secretion of biologically active substances of the thyroid gland. Somatotropin takes an active part in the growth of the body and protein synthesis. It can also affect glucose levels, lipid breakdown. This hormone is responsible for the normal physical development of the human body. An increase in its level leads to gigantism. If somatotropin is below normal (in children), then short stature is observed. By the way, different types of growth hormone (synthetic) are used in the fight against dwarfism, to increase weight in athletes. Prolactin is the main hormone responsible for milk production in women. Also, due to its production during breastfeeding, the next pregnancy does not occur. Melanotropin is produced in the middle lobe. The posterior lobe produces such types of human hormones as oxytocin, vasopressin. The first contributes to the contraction of the uterus, colostrum is produced. Vasopressin stimulates the muscles of organs such as the intestines, uterus, and blood vessels.

gonads

The ovaries and testicles produce sex hormones. Their types are as follows. First of all, they are divided into female and male. However, in small quantities they can be present in the opposite sex. Types of testosterone, androsterone, dihydrotestosterone, androstenediol. All of them provide the development of both primary sexual characteristics and secondary ones. It should be noted that their level does not tolerate such fluctuations compared to women's secrets. Thanks to testosterone, seminal fluid is produced, attraction to the opposite sex is stimulated. Also, the muscles, the skeleton develop in a special way, a characteristic male voice timbre appears. Other types of steroid hormones (in particular, dihydrotestosterone) provide male behavior, as well as a characteristic appearance: hair in certain areas, body structure. Types of female hormones are as follows: progesterone, estrogen, prolactin (produced by the pituitary gland).
Progesterone is produced by the corpus luteum. This gland is formed after ovulation. It performs the following functions: promotes the growth of the uterus, provides an opportunity for the egg (fertilized) to be fixed in its cavity. Progesterone prepares a woman for pregnancy, and also contributes to the bearing of a child. If the amount of the hormone is not enough, then the menstrual cycle will be disrupted, bleeding is possible. The low level of progesterone also affects the emotional state: as a rule, a woman suffers from sudden mood swings. An elevated level of the hormone may indicate either pregnancy or a tumor process. Estrogens are special types of hormones in women. These include estradiol, estrone, estriol. These substances are responsible for the formation of the female type of figure, increase the tone and elasticity of the skin. In addition, hormones of this type contribute to the normal course of menstruation. They also protect blood vessels from the accumulation of lipid plaques, promote the growth of bone tissue, and retain calcium and phosphorus in it. If the level of estrogen is insufficient, a male type of hair growth is observed, the skin ages earlier, excess weight accumulates in the abdomen, hips, bones become more fragile.

Blood test for sex hormones

Types of tests for hormones include the study of blood for the content of sexual secrets in it. It is prescribed if there are such violations: problems with the menstrual cycle, inability to conceive a child, miscarriage, etc. For men, such an analysis is indicated in cases of suspected tumor processes, infertility. Blood should be donated in the morning, before that you can not eat. On the eve it is worth giving up tobacco and alcohol, heavy physical exertion. A woman needs to choose the right time to take the test, since the level of hormones depends on the day of the menstrual cycle. Several indicators are being studied at the same time. The content in the maximum number indicates the onset of ovulation. In men, this hormone promotes the growth of the seminiferous tubules and affects the concentration of testosterone. When diagnosing infertility, special attention is paid to luteinizing hormone. In women, he is responsible for the maturation of the follicle, ovulation, the formation of such a gland as the corpus luteum. If it is impossible to become pregnant, the indicators of follicle-stimulating and luteinizing hormones are examined in combination. A blood test is also carried out for the presence of a certain amount of prolactin. With deviations from the norm, the onset of ovulation is difficult. Blood is also tested for testosterone. It is present in the body in both sexes. If its indicators are below the norm in men, then the quality of sperm deteriorates. It also negatively affects potency. In women, excess testosterone can cause miscarriage.

Biologically active substance (BAS), physiologically active substance (PAS) - a substance that in small quantities (mcg, ng) has a pronounced physiological effect on various functions of the body.

Hormone- a physiologically active substance produced or specialized endocrine cells, released into the internal environment of the body (blood, lymph) and has a distant effect on target cells.

Hormone - it is a signaling molecule secreted by endocrine cells that, through interaction with specific receptors on target cells, regulates their functions. Since hormones are information carriers, they, like other signaling molecules, have high biological activity and cause responses in target cells at very low concentrations (10 -6 - 10 -12 M/l).

Target cells (target tissues, target organs) - cells, tissues or organs that have specific receptors for a given hormone. Some hormones have a single target tissue, while others have effects throughout the body.

Table. Classification of physiologically active substances

Properties of hormones

Hormones have a number of common properties. They are usually formed by specialized endocrine cells. Hormones have a selective action, which is achieved by binding to specific receptors located on the surface of cells (membrane receptors) or inside them (intracellular receptors), and triggering a cascade of processes of intracellular hormonal signal transmission.

The sequence of events of hormonal signal transmission can be represented as a simplified scheme “hormone (signal, ligand) -> receptor -> second (secondary) messenger -> effector structures of the cell -> physiological response of the cell”. Most hormones lack species specificity (with the exception of ), which makes it possible to study their effects in animals, as well as to use hormones obtained from animals to treat sick people.

There are three variants of intercellular interaction with the help of hormones:

• endocrine(distant), when they are delivered to target cells from the place of production by blood;
• paracrine- hormones diffuse to the target cell from a nearby endocrine cell;
• autocrine - hormones act on the producer cell, which is also a target cell for it.

According to their chemical structure, hormones are divided into three groups:

• peptides (the number of amino acids up to 100, such as thyrotropin-releasing hormone, ACTH) and proteins (insulin, growth hormone, etc.);
• derivatives of amino acids: tyrosine (thyroxine, adrenaline), tryptophan - melatonin;
• steroids, cholesterol derivatives (female and male sex hormones, aldosterone, cortisol, calcitriol) and retinoic acid.

According to their function, hormones are divided into three groups:

• effector hormones acting directly on target cells;
• pituitary tron ​​hormones that control the function of peripheral endocrine glands;
• hypothalamic hormones that regulate the secretion of hormones by the pituitary gland.

Table. Types of action of hormones

Hormones circulate in the blood in a free (active form) and bound (inactive form) state with plasma proteins or formed elements. Free hormones are biologically active. Their content in the blood depends on the rate of secretion, the degree of binding, capture and metabolic rate in tissues (binding to specific receptors, destruction or inactivation in target cells or hepatocytes), removal with urine or bile.

Table. Physiologically active substances discovered recently

A number of hormones can undergo chemical transformations in target cells into more active forms. So, the hormone "thyroxine", undergoing deiodination, turns into a more active form - triiodothyronine. The male sex hormone testosterone in target cells can not only turn into a more active form - dehydrotestosterone, but also into the female sex hormones of the estrogen group.

The action of the hormone on the target cell is due to the binding, stimulation of a receptor specific to it, after which the hormonal signal is transmitted to the intracellular cascade of transformations. Signal transmission is accompanied by its multiple amplification, and the action of a small number of hormone molecules on a cell can be accompanied by a powerful response of target cells. Activation of the receptor by the hormone is also accompanied by the activation of intracellular mechanisms that stop the cell's response to the action of the hormone. These may be mechanisms that reduce the sensitivity (desensitization / adaptation) of the receptor to the hormone; mechanisms that dephosphorylate intracellular enzyme systems, etc.

Receptors for hormones, as well as for other signaling molecules, are localized on the cell membrane or inside the cell. Cell membrane receptors (1-TMS, 7-TMS and ligand-dependent ion channels) interact with hydrophilic (lyiophobic) hormones, for which the cell membrane is impermeable. They are catecholamines, melatonin, serotonin, protein-peptide hormones.

Hydrophobic (lipophilic) hormones diffuse through the plasma membrane and bind to intracellular receptors. These receptors are divided into cytosolic (receptors for steroid hormones - gluco- and mineralocorticoids, androgens and progestins) and nuclear (receptors for thyroid iodine-containing hormones, calcitriol, estrogens, retinoic acid). Cytosolic and estrogen receptors are bound to heat shock proteins (HSPs) to prevent their entry into the nucleus. The interaction of the hormone with the receptor leads to the separation of HSP, the formation of the hormone-receptor complex, and the activation of the receptor. The hormone-receptor complex moves to the nucleus, where it interacts with strictly defined hormone-sensitive (recognizing) DNA regions. This is accompanied by a change in the activity (expression) of certain genes that control the synthesis of proteins in the cell and other processes.

According to the use of certain intracellular pathways for the transmission of a hormonal signal, the most common hormones can be divided into a number of groups (Table 8.1).

Table 8.1. Intracellular mechanisms and pathways of action of hormones

Hormones control various reactions of target cells and through them - the physiological processes of the body. The physiological effects of hormones depend on their content in the blood, the number and sensitivity of receptors, and the state of post-receptor structures in target cells. Under the action of hormones, activation or inhibition of the energy and plastic metabolism of cells, the synthesis of various substances, including protein substances (metabolic action of hormones) can occur; change in the rate of cell division, its differentiation (morphogenetic action), initiation of programmed cell death (apoptosis); triggering and regulation of contraction and relaxation of smooth myocytes, secretion, absorption (kinetic action); changing the state of ion channels, accelerating or inhibiting the generation of electrical potentials in pacemakers (corrective action), facilitating or inhibiting the influence of other hormones (reactogenic action), etc.

Table. The distribution of the hormone in the blood

The rate of occurrence in the body and the duration of responses to the action of hormones depend on the type of stimulated receptors and the rate of metabolism of the hormones themselves. Changes in physiological processes can be observed after several tens of seconds and last for a short time upon stimulation of plasma membrane receptors (for example, vasoconstriction and an increase in blood pressure under the action of adrenaline) or occur after several tens of minutes and last for hours upon stimulation of nuclear receptors (for example, increased metabolism in cells and an increase in oxygen consumption by the body when thyroid receptors are stimulated by triiodothyronine).

Table. Time of action of physiologically active substances

Since the same cell can contain receptors for different hormones, it can simultaneously be a target cell for several hormones and other signaling molecules. The action of one hormone on a cell is often combined with the influence of other hormones, mediators, and cytokines. In this case, a number of signal transduction pathways can be triggered in target cells, as a result of the interaction of which an increase or inhibition of the cell response can be observed. For example, norepinephrine and can simultaneously act on a smooth myocyte of the vascular wall, summing up their vasoconstrictive effect. The vasoconstrictive effect of vasopressin can be eliminated or weakened by the simultaneous action of bradykinin or nitric oxide on smooth myocytes of the vascular wall.

Regulation of the formation and secretion of hormones

Regulation of the formation and secretion of hormones is one of the most important functions and nervous systems of the body. Among the mechanisms of regulation of the formation and secretion of hormones, there are the influence of the central nervous system, "triple" hormones, the influence of negative feedback channels on the concentration of hormones in the blood, the influence of the final effects of hormones on their secretion, the influence of daily and other rhythms.

Nervous regulation carried out in various endocrine glands and cells. This is the regulation of the formation and secretion of hormones by neurosecretory cells of the anterior hypothalamus in response to the flow of nerve impulses to it from various areas of the central nervous system. These cells have a unique ability to be excited and transform excitation into the formation and secretion of hormones that stimulate (releasing hormones, liberins) or inhibit (statins) the secretion of hormones by the pituitary gland. For example, with an increase in the flow of nerve impulses to the hypothalamus under conditions of psychoemotional arousal, hunger, pain, exposure to heat or cold, during infection and other emergency conditions, the neurosecretory cells of the hypothalamus release corticotropin-releasing hormone into the portal vessels of the pituitary gland, which enhances the secretion of adrenocorticotropic hormone. (ACTH) by the pituitary gland.

ANS has a direct effect on the formation and secretion of hormones. With an increase in the tone of the SNS, the secretion of triple hormones by the pituitary gland increases, the secretion of catecholamines by the adrenal medulla, thyroid hormones by the thyroid gland, and insulin secretion decreases. With an increase in the tone of the PSNS, the secretion of insulin and gastrin increases and the secretion of thyroid hormones is inhibited.

Regulation by tron ​​hormones of the pituitary gland used to control the formation and secretion of hormones by peripheral endocrine glands (thyroid, adrenal cortex, gonads). The secretion of tropic hormones is under the control of the hypothalamus. Tropic hormones get their name from their ability to bind (have affinity) to receptors on target cells that form individual peripheral endocrine glands. The tropic hormone to thyrocytes of the thyroid gland is called thyrotropin or thyroid stimulating hormone (TSH), to the endocrine cells of the adrenal cortex is called adrenocorticotropic hormone (ACTH). Tropic hormones to the endocrine cells of the gonads are called: lutropin or luteinizing hormone (LH) - to the Leydig cells, the corpus luteum; follitropin or follicle-stimulating hormone (FSH) - to follicle cells and Sertoli cells.

Tropic hormones, when their level in the blood increases, repeatedly stimulate the secretion of hormones by the peripheral endocrine glands. They may also have other effects on them. So, for example, TSH increases blood flow in the thyroid gland, activates metabolic processes in thyrocytes, their uptake of iodine from the blood, and accelerates the processes of synthesis and secretion of thyroid hormones. With an excess amount of TSH, hypertrophy of the thyroid gland is observed.

Feedback regulation used to control the secretion of hormones from the hypothalamus and pituitary gland. Its essence lies in the fact that the neurosecretory cells of the hypothalamus have receptors and are target cells for the hormones of the peripheral endocrine gland and the triple hormone of the pituitary gland, which controls the secretion of hormones by this peripheral gland. Thus, if TSH secretion increases under the influence of hypothalamic thyrotropin-releasing hormone (TRH), the latter will bind not only to thyrocyte receptors, but also to receptors of neurosecretory cells of the hypothalamus. In the thyroid gland, TSH stimulates the production of thyroid hormones, while in the hypothalamus it inhibits further secretion of TRH. The relationship between the level of TSH in the blood and the processes of formation and secretion of TRH in the hypothalamus is called short loop feedback.

The secretion of TRH in the hypothalamus is also influenced by the level of thyroid hormones. If their concentration in the blood increases, then they bind to the thyroid hormone receptors of the neurosecretory cells of the hypothalamus and inhibit the synthesis and secretion of TRH. The relationship between the level of thyroid hormones in the blood and the processes of formation and secretion of TRH in the hypothalamus is called long loop feedback. There is experimental evidence that the hormones of the hypothalamus not only regulate the synthesis and release of pituitary hormones, but also inhibit their own release, which is defined by the concept ultra short loop feedback.

The totality of the glandular cells of the pituitary, hypothalamus and peripheral endocrine glands and the mechanisms of their mutual influence on each other were called systems or axes of the pituitary - hypothalamus - endocrine gland. The systems (axes) of the pituitary gland - hypothalamus - thyroid gland are distinguished; pituitary - hypothalamus - adrenal cortex; pituitary - hypothalamus - sex glands.

Influence of end effects hormones on their secretion takes place in the islet apparatus of the pancreas, C-cells of the thyroid gland, parathyroid glands, hypothalamus, etc. This is demonstrated by the following examples. An increase in blood glucose stimulates the secretion of insulin, and a decrease stimulates the secretion of glucagon. These hormones inhibit each other's secretion by a paracrine mechanism. With an increase in the level of Ca 2+ ions in the blood, the secretion of calcitonin is stimulated, and with a decrease - parathyrin. The direct influence of the concentration of substances on the secretion of hormones that control their level is a quick and effective way to maintain the concentration of these substances in the blood.

Among the considered mechanisms of regulation of hormone secretion, their final effects include the regulation of secretion of antidiuretic hormone (ADH) by the cells of the posterior hypothalamus. The secretion of this hormone is stimulated by an increase in the osmotic pressure of the blood, such as fluid loss. Reduced diuresis and fluid retention in the body under the action of ADH lead to a decrease in osmotic pressure and inhibition of ADH secretion. A similar mechanism is used to regulate the secretion of natriuretic peptide by atrial cells.

Influence of circadian and other rhythms on the secretion of hormones takes place in the hypothalamus, adrenal glands, sex, pineal glands. An example of the influence of the circadian rhythm is the daily dependence of the secretion of ACTH and corticosteroid hormones. Their lowest level in the blood is observed at midnight, and the highest - in the morning after waking up. The highest level of melatonin is recorded at night. The influence of the lunar cycle on the secretion of sex hormones in women is well known.

Definition of hormones

secretion of hormones the entry of hormones into the internal environment of the body. Polypeptide hormones accumulate in granules and are secreted by exocytosis. Steroid hormones do not accumulate in the cell and are secreted immediately after synthesis by diffusion through the cell membrane. The secretion of hormones in most cases has a cyclic, pulsating character. The frequency of secretion is from 5-10 minutes to 24 hours or more (a common rhythm is about 1 hour).

Bound form of the hormone- the formation of reversible complexes of hormones connected by non-covalent bonds with plasma proteins and formed elements. The degree of binding of various hormones varies greatly and is determined by their solubility in blood plasma and the presence of a transport protein. For example, 90% of cortisol, 98% of testosterone and estradiol, 96% of triiodothyronine and 99% of thyroxine bind to transport proteins. The bound form of the hormone cannot interact with receptors and forms a reserve that can be quickly mobilized to replenish the free hormone pool.

free form hormone- a physiologically active substance in the blood plasma in a protein-free state, capable of interacting with receptors. The bound form of the hormone is in dynamic equilibrium with the pool of free hormone, which in turn is in equilibrium with the hormone bound to receptors in target cells. Most polypeptide hormones, with the exception of somatotropin and oxytocin, circulate in low concentrations in the blood in a free state, without binding to proteins.

Metabolic transformations of the hormone - its chemical modification in target tissues or other formations, causing a decrease / increase in hormonal activity. The most important place for the exchange of hormones (their activation or inactivation) is the liver.

Hormone metabolism rate - the intensity of its chemical transformation, which determines the duration of circulation in the blood. The half-life of catecholamines and polypeptide hormones is several minutes, and that of thyroid and steroid hormones is from 30 minutes to several days.

hormone receptor- a highly specialized cellular structure that is part of the plasma membranes, cytoplasm or nuclear apparatus of the cell and forms a specific complex compound with the hormone.

The organ specificity of the action of the hormone - responses of organs and tissues to physiologically active substances; they are strictly specific and cannot be called by other compounds.

Feedback- the influence of the level of circulating hormone on its synthesis in endocrine cells. A long feedback chain is the interaction of the peripheral endocrine gland with the pituitary, hypothalamic centers and with the suprahypothalamic regions of the central nervous system. A short feedback chain - a change in the secretion of the pituitary tron ​​hormone, modifies the secretion and release of statins and liberins of the hypothalamus. An ultrashort feedback chain is an interaction within an endocrine gland in which the secretion of a hormone affects the secretion and release of itself and other hormones from that gland.

Negative feedback - an increase in the level of the hormone, leading to inhibition of its secretion.

positive feedback- an increase in the level of the hormone, which causes stimulation and the appearance of a peak of its secretion.

Anabolic hormones - physiologically active substances that promote the formation and renewal of the structural parts of the body and the accumulation of energy in it. These substances include pituitary gonadotropic hormones (follitropin, lutropin), sex steroid hormones (androgens and estrogens), growth hormone (somatotropin), placental chorionic gonadotropin, and insulin.

Insulin- a protein substance produced in β-cells of the islets of Langerhans, consisting of two polypeptide chains (A-chain - 21 amino acids, B-chain - 30), which reduces blood glucose levels. The first protein whose primary structure was completely determined by F. Sanger in 1945-1954.

catabolic hormones- physiologically active substances that contribute to the breakdown of various substances and structures of the body and the release of energy from it. These substances include corticotropin, glucocorticoids (cortisol), glucagon, high concentrations of thyroxine and adrenaline.

Thyroxine (tetraiodothyronine) - an iodine-containing derivative of the amino acid tyrosine, produced in the follicles of the thyroid gland, which increases the intensity of basal metabolism, heat production, which affects the growth and differentiation of tissues.

Glucagon - a polypeptide produced in a-cells of the islets of Langerhans, consisting of 29 amino acid residues, stimulating the breakdown of glycogen and increasing blood glucose levels.

Corticosteroid hormones - compounds formed in the adrenal cortex. Depending on the number of carbon atoms in the molecule, they are divided into C 18 -steroids - female sex hormones - estrogens, C 19 -steroids - male sex hormones - androgens, C 21 -steroids - corticosteroid hormones proper, which have a specific physiological effect.

Catecholamines - derivatives of pyrocatechin, actively involved in physiological processes in the body of animals and humans. The catecholamines include epinephrine, norepinephrine, and dopamine.

Sympathoadrenal system - chromaffin cells of the adrenal medulla and the preganglionic fibers of the sympathetic nervous system innervating them, in which catecholamines are synthesized. Chromaffin cells are also found in the aorta, carotid sinus, and within and near the sympathetic ganglia.

Biogenic amines- a group of nitrogen-containing organic compounds formed in the body by decarboxylation of amino acids, i.e. cleavage from them of the carboxyl group - COOH. Many of the biogenic amines (histamine, serotonin, norepinephrine, adrenaline, dopamine, tyramine, etc.) have a pronounced physiological effect.

Eicosanoids - physiologically active substances, predominantly derivatives of arachidonic acid, which have a variety of physiological effects and are divided into groups: prostaglandins, prostacyclins, thromboxanes, levuglandins, leukotrienes, etc.

Regulatory peptides- macromolecular compounds, which are a chain of amino acid residues connected by a peptide bond. Regulatory peptides with up to 10 amino acid residues are called oligopeptides, from 10 to 50 - polypeptides, more than 50 - proteins.

Antihormone- a protective substance produced by the body with prolonged administration of protein hormonal preparations. The formation of an antihormone is an immunological reaction to the introduction of a foreign protein from outside. In relation to its own hormones, the body does not form antihormones. However, substances similar in structure to hormones can be synthesized, which, when introduced into the body, act as antimetabolites of hormones.

Hormone antimetabolites- physiologically active compounds that are similar in structure to hormones and enter into competitive, antagonistic relationships with them. Antimetabolites of hormones are able to take their place in the physiological processes occurring in the body, or block hormone receptors.

Tissue hormone (autocoid, local hormone) - a physiologically active substance produced by non-specialized cells and having a predominantly local effect.

Neurohormone- a physiologically active substance produced by nerve cells.

The effector hormone a physiologically active substance that has a direct effect on cells and target organs.

throne hormone- a physiologically active substance that acts on other endocrine glands and regulates their functions.

Hormones- signal chemicals released by the endocrine glands directly into the blood and have a complex and multifaceted effect on the body as a whole or on certain organs and target tissues. Hormones serve as humoral (blood-borne) regulators of certain processes in certain organs and systems. There are other definitions, according to which the interpretation of the concept of a hormone is broader: "signaling chemicals produced by the cells of the body and affecting the cells of other parts of the body." This definition seems to be preferable, as it covers many substances traditionally classified as hormones: animal hormones that lack a circulatory system (for example, ecdysones of roundworms, etc.), vertebrate hormones that are not produced in the endocrine glands (prostaglandins, erythropoietin, etc.) and plant hormones.

Currently, more than one and a half hundred hormones from various multicellular organisms have been described and isolated. According to their chemical structure, they are divided into three groups: protein-peptide, amino acid derivatives and steroid hormones.

The first group is the hormones of the hypothalamus and pituitary, pancreas and parathyroid glands and the thyroid hormone calcitonin. Some hormones, such as follicle-stimulating and thyroid-stimulating hormones, are glycoproteins - peptide chains “decorated” with carbohydrates.

Amino acid derivatives- These are amines that are synthesized in the adrenal medulla (adrenaline and noradrenaline) and in the pineal gland (melatonin), as well as iodine-containing thyroid hormones triiodothyronine and thyroxine (tetraiodothyronine).

The third group is precisely responsible for the frivolous reputation that hormones have acquired among the people: these are steroid hormones that are synthesized in the adrenal cortex and in the gonads. Looking at their general formula, it is easy to guess that their biosynthetic precursor is cholesterol. Steroids differ in the number of carbon atoms in the molecule: C21 - hormones of the adrenal cortex and progesterone, C19 - male sex hormones (androgens and testosterone), C18 - female sex hormones (estrogens).

Hydrophilic hormone molecules, such as protein-peptide ones, are usually transported by the blood in a free form, while steroid hormones or iodine-containing thyroid hormones are usually transported in the form of complexes with blood plasma proteins. By the way, protein complexes can also act as a hormone reserve pool; when the free form of the hormone is destroyed, the complex with the protein dissociates and thus the desired concentration of the signal molecule is maintained.

Having reached the target, the hormone binds to the receptor - a protein molecule, one part of which is responsible for binding, receiving a signal, the other - for transmitting the effect "on the relay" into the cell. (As a rule, this changes the activity of any enzymes.) Receptors for hydrophilic hormones are located on the membranes of target cells, and lipophilic hormones are inside the cells, since lipophilic molecules can penetrate the membrane. Signals from receptors are received by the so-called second messengers, or intermediaries, which are much less diverse than the hormones themselves. Here we meet such familiar characters as cyclo-AMP, G-proteins, protein kinases - enzymes that attach phosphate groups to proteins, thereby generating new signals. Now let's rise again from the cellular level to the level of organs and tissues. From this point of view, everything begins in the hypothalamus and pituitary gland. The functions of the hypothalamus are diverse and even today not fully understood, but probably everyone agrees that the hypothalamic-pituitary complex is the central point of interaction between the nervous and endocrine systems. The hypothalamus is both a center for the regulation of autonomic functions and a “cradle of emotions”. It produces releasing hormones (from the English release - to release), they are also liberins that stimulate the release of hormones by the pituitary gland, as well as statins that inhibit this release.

Pituitary- an endocrine organ located on the inner surface of the brain. It produces tropic hormones (Greek tropos - direction), which are called so because they direct the work of other, peripheral endocrine glands - the adrenal glands, thyroid and parathyroid, pancreas, gonads. Moreover, this scheme is saturated with feedbacks, for example, the female hormone estradiol, entering the pituitary gland, regulates the secretion of triple hormones that control its own secretion. Therefore, the amount of the hormone, firstly, is not excessive, and secondly, various endocrine processes are finely coordinated with each other. The time regulation deserves special attention. The “built-in clock” of our body is the pineal gland, the pineal gland that produces the hormone melatonin (a derivative of the amino acid tryptophan). Fluctuations in the concentration of this substance create a sense of time in a person, and the nature of these fluctuations determines whether a person will be an “owl” or a “lark”. The concentration of very many hormones also changes cyclically during the day. That is why endocrinologists sometimes require patients to collect daily urine (the sum may turn out to be a more constant and characteristic value than the terms), and sometimes, if you need to evaluate the dynamics, they take tests every hour.

growth hormone(STG) has an effect on the entire body - it stimulates growth and regulates metabolic processes accordingly.

Pituitary tumors that cause overproduction of this hormone cause gigantism in humans and animals. If the tumor does not occur in childhood, but later, acromegaly develops - an uneven growth of the skeleton, mainly due to cartilaginous areas. Insufficiency of growth hormone, on the contrary, leads to dwarfism, or pituitary dwarfism. Fortunately, modern medicine treats this. If the doctor establishes that the reason for the child’s too slow growth (not even necessarily dwarfism, but simply lagging behind peers) is precisely in the low concentration of growth hormone, and considers it necessary to prescribe hormone injections, then growth will normalize. But the story of the Soviet science fiction writer Alexander Belyaev “The Man Who Found His Face” is still a fairy tale: hormonal injections will not help an adult grow up.

The pituitary gland also produces prolactin, which is also lactogenic and luteotropic hormone (LTH), which is responsible for lactation during breastfeeding. In addition, lipotropins are synthesized in the pituitary gland - hormones that stimulate the involvement of fat in energy metabolism. These same hormones are the precursors of endorphins - "happy peptides".

Pituitary melanocyte-stimulating hormones (MSH) regulate the synthesis of pigments in the skin and, in addition, judging by some evidence, have something to do with memory mechanisms. Two more important hormones are vasopressin and oxytocin; the first is also called antidiuretic hormone, it regulates water-salt metabolism and arteriole tone; Oxytocin is responsible for uterine contractions in mammals and, together with prolactin, for milk. It is used to induce labor. Now more about the tropic hormones that the pituitary gland produces and their targets.

adrenal glands- paired organs adjacent to the tops of the kidneys. In each of them, two independent glands are distinguished: the cortex (substantia corticalis) and the medulla. The purpose of adrenocorticotropic hormone (ACTH, aka corticotropin) is the adrenal cortex. This is where corticosteroids are synthesized. Glucocorticoids (cortisol and others) get their name from glucose because their activity is closely related to carbohydrate metabolism.

Cortisol is a stress hormone, it protects the body from any sudden changes in physiological balance: it affects the metabolism of carbohydrates, proteins and lipids, and electrolyte balance. However, the latter is more in the department of mineralocorticoids: their main representative, aldosterone, regulates the exchange of sodium, potassium and hydrogen ions. Corticosteroids and their artificial analogues are widely used in medicine. Glucocorticoids have another important property: they suppress inflammatory reactions and reduce the formation of antibodies, therefore, ointments are made on their basis for the treatment of skin inflammation and itching. By the way, some skin ointments of Chinese origin, popular among lovers of alternative medicine, contain the same glucocorticoids in addition to plant extracts. This is written in plain text on the packaging, but buyers do not always pay attention to complex biochemical words. Although, perhaps, it would be better to purchase a banal fluorocort for the treatment of dermatitis, it is at least allowed by the Russian pharmacopoeia ...

The adrenal medulla produces the catecholamines adrenaline and norepinephrine. Everyone knows today that adrenaline is synonymous with stress. It is responsible for the mobilization of adaptive responses: it acts on metabolism, on the cardiovascular system, and on carbohydrate and fat metabolism. Catecholamines are the simplest in structure and, obviously, the oldest signal substances; it is not for nothing that they are found even in Protozoa. But they play a special role as neurotransmitters only in multicellular organisms. We'll talk about this another time.

Pancreas- simultaneously exocrine and endocrine, that is, it works both outside and inside: it secretes enzymes into the duodenum (biologists consider the contents of the digestive tract as an environment external to the body), and hormones into the blood.

In special glandular formations, the islets of Langerhans, alpha cells produce glucagon, a regulator of carbohydrate and fat metabolism, and beta cells produce insulin. This hormone was discovered by the Russian scientist L.V. Sobolev (1902). Insulin was first identified by Canadian physiologists Frederick Banting, Charles Best, and John McLeod (1921). Banting and McLeod received the Nobel Prize in 1923 for this. (Best, who served as a laboratory assistant, was not included in the number of laureates, and an indignant Banting gave the assistant half of his award.)

The structural unit of insulin is a monomer with a molecular weight of about 6000, and from two to six monomers are combined into a molecule. The sequence of amino acids in the insulin monomer (that is, its primary structure) was first established by the English biochemist Frederick Sanger (1956, Nobel Prize in Chemistry 1958), and the spatial structure was again established by the Englishwoman and also Nobel laureate Dorothy Hodgkin (1972). Each monomer contains 51 amino acids, which are arranged in the form of two peptide chains - A and B, connected by two disulfide bridges (-S-S-).

Insulin. This hormone lowers blood sugar by delaying the breakdown of glycogen and glucose synthesis in the liver, while at the same time increasing the permeability of cell membranes to glucose. It also promotes the absorption of this fuel, stimulates the synthesis of proteins and fats at the expense of carbohydrates. Thus, he is responsible for the fact that the cells absorb glucose from the blood and “digest” it well.

Lack of insulin - high blood sugar and "hungry" cells, tissues and organs, in other words, diabetes. Probably the most famous endocrine disease. In particular, because insulin is the first artificially synthesized peptide hormone that replaced drugs obtained from the pancreas of slaughtered cattle. Now doctors are dreaming of even more radical successes - for example, to introduce stem cells that produce insulin into the patient's body. The introduction of such a technique into clinical practice is not an easy and fast matter, but insulin injections provide a normal life for many people today.

pituitary thyroid stimulating hormone(TSH) acts on the thyroid gland (glandula thyroidea), which in us humans is located in the neck, under the larynx. Its hormones are thyroxine and triiodothyronine, regulators of metabolism, protein synthesis, tissue differentiation, development and growth of the body. Their biochemical precursor is the amino acid tyrosine. Since the thyroid hormone molecules contain iodine, a deficiency of this element in the diet leads to a hormone deficiency.

Clinical manifestations - growth of the gland (goiter) with a decrease in its function. Toxic goiter, also known as Graves' disease, or thyrotoxicosis, on the contrary, is associated with hyperfunction of the gland and an excess of hormones. The thyroid gland also synthesizes a hormone that regulates the metabolism of calcium and phosphorus, calcitonin. And another hormone that regulates the exchange of these same elements is produced by paired parathyroid (parathyroideae) glands - it is called parathyroid hormone. These hormones, along with vitamin D, are responsible for bone growth and repair.

Gonadotropic hormones of the pituitary gland- luteinizing hormone (LH), gonadotropin, follicle-stimulating hormone FSH regulate the activity of the sex glands. (Finally got to them.) Testosterone - the main androgen - is produced by the testes in men, and in women - by the adrenal cortex and ovaries. At the stage of intrauterine development, this hormone in men directs the differentiation of the genital organs, and during puberty - the development of secondary sexual characteristics, as well as the formation of male sexual orientation.

In adults, testosterone ensures the normal functioning of the genital organs. By the way, the testicles of a boy's embryo also produce a regression factor of the Mullerian channels - a hormone that blocks the development of the female reproductive system. Thus, in the embryonic period, the development of the boy is accompanied by chemical signals that girls do not have, and from here all other differences ultimately arise. As experts joke about this, “to get a boy, you need to do something, if you do nothing, you get a girl.” Estrogens in women are synthesized in ovaries. Estradiol, one of the main estrogens, is responsible for the formation of secondary female sexual characteristics and is involved in the regulation of the monthly cycle.

Progestins(progesterone and its derivatives) are needed both for the regulation of the cycle and for the normal course of pregnancy. Without fertilization, in a certain period of the cycle and in the first 12 weeks, progesterone is synthesized by the cells of the corpus luteum of the ovaries, and then by the placenta. Progesterone is also secreted in small amounts by the adrenal cortex and, in men, by the testes. Tellingly, progesterone is an intermediate in the synthesis of androgens.

In the ovaries, relaxin is also synthesized - the hormone of childbirth, which is responsible, for example, for relaxing the ligaments of the pelvis. But perhaps not a single substance contained in the human body evokes as many emotions in the fair sex as human chorionic gonadotropin. The fetal placenta can also be considered as an endocrine organ: it synthesizes both progestin and relaxin, and many other hormones and hormone-like substances. The unborn child constantly exchanges signals with the mother's body, creating conditions suitable for itself. One of the early attempts of the fetus to establish contact with the mother is just this glycoprotein, chorionic gonadotropin, also known as HCG or HCG. The presence of it in the blood or urine of a woman means that the patient is in position, and the absence means that pregnancy, alas (or cheers), has not occurred. In the middle of the last century, this fateful analysis was completely barbaric: a woman injected urine into mice and looked to see if the animals showed symptoms of pregnancy. Now it is elegantly simple, you don't even have to go to the doctor, just buy a pregnancy test at the pharmacy, aka a "strip" - a narrow strip in an envelope, in fact, a miniature chromatographic paper.

It is difficult to find another example when the improvement of the routine methods of biochemical analysis would have so strongly influenced human destinies. How many safely preserved pregnancies and how many abortions were done on time ... Well, yes, without a doubt, abortion is bad. But to arrange so that people do not do stupid things is not in the competence of medicine. With this - to psychologists, teachers and economists. Doctors and scientists can only minimize the harm caused by stupidity.

Mechanisms of action of hormones When a hormone in the blood reaches the target cell, it interacts with specific receptors; receptors "read the message" of the body, and certain changes begin to occur in the cell. Each specific hormone corresponds exclusively to "its" receptors located in specific organs and tissues - only when the hormone interacts with them, a hormone-receptor complex is formed.

The mechanisms of action of hormones can be different. One group is made up of hormones that bind to receptors located inside cells - usually in the cytoplasm. These include hormones with lipophilic properties - for example, steroid hormones (sex, gluco- and mineralocorticoids), as well as thyroid hormones. Being fat-soluble, these hormones easily penetrate the cell membrane and begin to interact with receptors in the cytoplasm or nucleus. They are slightly soluble in water, and when transported through the blood, they bind to carrier proteins. It is believed that in this group of hormones, the hormone-receptor complex plays the role of a kind of intracellular relay - having formed in the cell, it begins to interact with chromatin, which is located in the cell nuclei and consists of DNA and protein, and thereby speeds up or slows down the work of certain genes. . By selectively influencing a specific gene, the hormone changes the concentration of the corresponding RNA and protein, and at the same time corrects metabolic processes.

The biological result of the action of each hormone is very specific. Although hormones usually change less than 1% of proteins and RNA in the target cell, this is quite enough to obtain the corresponding physiological effect. Most other hormones are characterized by three features:

• they dissolve in water;
• do not bind to carrier proteins;
• they begin the hormonal process as soon as they are connected to the receptor, which can be located in the cell nucleus, its cytoplasm, or located on the surface of the plasma membrane.

The mechanism of action of the hormone-receptor complex of such hormones necessarily involves mediators that induce a cell response. The most important of these mediators are cAMP (cyclic adenosine monophosphate), inositol triphosphate, and calcium ions. So, in an environment devoid of calcium ions, or in cells with insufficient amounts of them, the action of many hormones is weakened; when using substances that increase the intracellular concentration of calcium, there are effects that are identical to the effects of some hormones.

The participation of calcium ions as a mediator provides an effect on the cells of such hormones as vasopressin and catecholamines. However, there are hormones in which an intracellular mediator has not yet been found. Of the best known of these hormones, one can name insulin, in which cAMP and cGMP, as well as calcium ions and even hydrogen peroxide, have been proposed as an intermediary, but there is still no convincing evidence in favor of any one substance. Many researchers believe that in this case, chemical compounds can act as mediators, the structure of which is completely different from the structure of mediators already known to science. Having completed their task, hormones are either broken down in target cells or in the blood, or transported to the liver, where they are broken down, or finally eliminated from the body mainly in the urine (for example, adrenaline).

Hormones, types of hormones and their influence

Hormones are biologically highly active substances produced in the endocrine glands. Hormones enter the bloodstream and are very far away, but precisely in those tissues that will be regulated by them. The amount of hormones in the body depends on many factors, including the time of day and the age of the woman or man. The life support of the reproductive function of a woman is carried out through the hypothalamus-pituitary-ovaries system precisely with the help of these biologically active substances, that is, hormones, and only an analysis for hormones will help to get a clear picture.

The term “hormone” itself comes from the Greek word for “excite”.

We naively believe that we make decisions on our own, of our own free will show interest in someone, and reject someone, of our own free will unite our fate with someone. In fact, very many of our actions - especially when it comes to communicating with the opposite sex - are controlled by amazing, full of mysteries and secrets, chemical compounds - hormones. Women are women in every sense of the word and with all the ensuing consequences, precisely under the influence of female hormones. This also applies to men, only they are led by male hormones. However, in every woman there is a little bit of a man, and in every man there is a little bit of a woman. In the hormonal sense of these words.

female hormones

ESTROGEN is the most feminine hormone. It is synthesized by the ovaries. Estrogen causes the regularity of the menstrual cycle, in girls it causes the formation of secondary sexual characteristics (enlargement of the mammary glands, growth of pubic and armpit hair, a characteristic shape of the pelvis). In addition, during puberty, estrogen helps the girl's body prepare for a future sex life and motherhood - this applies to many points related to the state of the external genitalia and uterus. Thanks to estrogen, an adult woman maintains youth and beauty, good skin condition and a positive attitude towards life. If the amount of estrogen in the female body is normal, the woman, as a rule, feels great and often looks younger than her peers with a disturbed hormonal background. Estrogen is also responsible for a woman's desire to nurse and protect her nest.

DATA:

Since estrogen has a calming effect, it is given to aggressive men in prisons - it is believed that this helps to cope with outbursts of anger.

Estrogen also improves memory. That is why women during menopause, when ovarian failure causes a drop in estrogen levels in the body, often have difficulty remembering. Usually, hormone replacement therapy helps to cope with this, which protects a woman in menopause, and from other health-related troubles.

Estrogen causes the female body to store fat. This is very upsetting for women, but it causes enthusiasm among livestock breeders: thanks to the estrogen introduced into the feed, farm animals are remarkably gaining weight.

An indicator of a high level of estrogen in the blood and, therefore, a high ability to conceive a child is a light hair color. Perhaps men, instinctively feeling the fertility of blondes, have an increased interest in them. However, after the birth of the first child, the level of estrogen in the body of a woman decreases, and her hair darkens. Two or three children, and the husband wonders why his beloved blonde wife has darkened her hair.

PROGESTERONE - a hormone that contributes to the timely onset and normal development of pregnancy. Progesterone is produced by the corpus luteum (Corpus luteum) of the ovaries, placenta, and adrenal glands. It is called the hormone of parental instinct: thanks to progesterone, a woman not only physically prepares for the birth of a child, but also experiences psychological changes.

Progesterone prepares the lining of the uterus to receive a fertilized egg. After fertilization, progesterone begins to be synthesized in the placenta, ensuring the normal course of pregnancy. Progesterone also prepares the mammary glands of a woman to produce milk when a child is born.

The female sex hormone progesterone is a progestogen. The concentration of progesterone in the blood varies according to the life cycle.

DATA:

The level of progesterone in the blood of a woman rises when she sees small children. Some researchers believe that this is caused by a signal tentatively called "the shape of the baby." It has been established that an increase in progesterone in a woman's blood causes the appearance of a small, plump body with a large head and large eyes. This reaction is so strong that progesterone is actively released, even if a woman sees a "baby-like" soft toy, such as a bear. Most men remain completely indifferent to soft and thick toy bears.

PROLACTIN This hormone is produced by the pituitary gland, a pea-sized gland located in the brain. The biological role of prolactin is to ensure the growth and development of the mammary glands and intensive stimulation of milk production during the period of feeding a child. This hormone is called stress - its content increases with increased physical exertion, overwork, psychological trauma.

DATA:

An "unauthorized" increase in the level of prolactin can cause diseases of the mammary glands - for example, mastopathy, as well as discomfort in the mammary glands during "critical days".

Male hormones (androgens)

TESTOSTERONE - the most male hormone. It is produced by the adrenal glands and testicles. Testosterone is called the aggression hormone. He makes a man hunt and kill prey. Thanks to testosterone, a man is set to provide food and protect his home and family. In modern society, this hormone is fraught with some danger for men, because in order to feed a family, there is now no need to run through the forest and throw spears. In order for the testosterone level to be kept normal, a man needs physical activity - modern representatives of the stronger sex replace the ancient hunt with a modern gym.

During puberty, a young man's testosterone levels skyrocket, turning him into a lean, fast, and purposeful "machine" for getting food. In the same period, under the influence of androgens, the young man turns into a man capable of fertilization.

DATA:

Thanks to testosterone, a beard grows in men and the likelihood of baldness increases, the voice becomes deep and the ability to navigate in space develops. Possessors of lower voices demonstrate higher sexual activity.

In people treated with testosterone, the ability to read road maps improves.

Testosterone levels decrease in people who drink alcohol excessively, as well as in smokers.

The level of testosterone in men becomes lower and at the age of 50-60, they become less aggressive and are more willing to babysit children or their other relatives.

Male hormones, among which testosterone is the leading one, are not suitable for use in agriculture - well, who needs a muscular cow or a pig? But steroids, male hormones, are actively used by athletes in order to quickly build muscle mass. This is done not only by men, but also by women. However, both those and others pay for the use of steroids with hormonal disorders.

"General" hormones

Androgens (including testosterone) in the female body are produced in small quantities in the ovaries and adrenal glands. In some diseases, the level of androgens in the blood of a woman rises, which causes increased body hair growth, a lowering of the voice. Therefore, if you, dear ladies, are concerned about the amount of hair in various parts of the body and their location, contact an endocrinologist for complete peace of mind - he will explain what is the norm and what is a deviation from the norm. Do not be afraid in vain: a certain degree of hairiness is inherent in quite healthy women.

DATA:

During menopause, a woman's levels of the female hormone estrogen decrease and testosterone levels rise. At the age of 45-50, a woman can become more independent and decisive than before and discover the ability for entrepreneurial activity. Among the disadvantages of such a surprise of nature are the likelihood of facial hair growth in a woman, a tendency to stress and an increased likelihood of developing a stroke.

The situation becomes critical

Between the 21st and 28th day of the monthly cycle, the level of female hormones in the blood drops sharply, which leads to the onset of acute symptoms of depression, known as "menstrual tension (MN)". It is these days that can rightly be called critical. It is no coincidence that most women feel in this phase, to put it mildly, not in the best way. It is during this period that women become irritable, aggressive, tired, whiny; many have disturbed sleep, headaches intensify; some even become depressed; some develop acne, pain in the lower abdomen, engorgement of the mammary glands, swelling of the legs and face, constipation, increased blood pressure with headaches to nausea and vomiting. This is due to an excess (estrogen) or deficiency (progesterone) of the hormones. Something similar happens in menopause (usually at 40 or just after 50): a woman undergoes significant psychological, emotional and hormonal changes.

Hormones and sex

It is known that hormones and sex are closely related to each other. First of all, sex contributes to the production of endorphins - the so-called "happiness hormones". And they, among many effects, also have an analgesic effect. Therefore, if a tooth hurts, it's time to have sex. (By the way, sex, like intense physical activity, improves blood circulation in the body, including in the oral cavity. This makes gums healthier and prevents many dental problems.) And that's not all. Regular sexual activity also releases hormones such as adrenaline and cortisone, which stimulate the brain and prevent migraines.

Doctors believe that sex increases our ability to focus, stimulates attention and creative thinking. In addition, sexual activity prolongs life: those who make love regularly (at least 2 times a week) live much longer than those who remember sex less than once a month.

Be patient, you are men!

The male sex hormone testosterone helps to endure pain. As American scientists have established, it reduces the level of discomfort, making a person less susceptible to pain, contributing to the production of natural painkillers - enkephalins. True, so far it has been possible to demonstrate the correctness of this statement only in experiments on sparrows.

Family matters

Relationships in the family are also subject to hormones. Moreover, it is important in what proportion the levels of testosterone in the spouses are combined.

It turns out that men with below average testosterone levels in the blood feel great in marriage with women who have the same hormone - above average levels. Such a wife perfectly supports her husband, has a more flexible psyche and understands her husband better - after all, a high level of testosterone makes a person more assertive, and this can be expressed both in aggression and in the desire to help loved ones. If, for example, both spouses have a level below the average, then there is a positive point here - they are more positive when discussing family problems.

Combining all the data, the scientists came to a revolutionary conclusion - before you get married, find out the level of male hubbub in yourself and your chosen one. Otherwise, how will you solve problems?

Which hormone is responsible for what?

Our ability to have children largely depends on how different hormones get along with each other. How to understand the results of hormonal tests?

To determine the usefulness of the hormonal background, it is necessary to take tests for hormones. Be careful, hormones are very sensitive to all external changes. Each hormone has its own little "whims". An accurate and indicative determination of the level of hormones in the blood depends not only on the specific day of the woman's menstrual cycle, but also on the time that has elapsed since the last meal.

ABC of the patient

FSH- follicle stimulating hormone

LG- luteinizing hormone

TSH- thyroid-stimulating hormone

BRL- prolactin

T3- triiodothyronine

T4- thyroxine

Testosterone

Thyroid

Thyroid-stimulating hormone controls the activity of the thyroid gland, "forces" it to produce the hormones thyroxine and triiodothyronine.

thyroxine regulates the metabolism, energy, oxygen, as well as body temperature, the processes of synthesis and breakdown of proteins, fats and carbohydrates, participates in the processes of growth, development and reproduction.

Triiodothyronine Formed from thyroxine, regulates metabolism, growth, development and energy generation in the body.

pituitary (brain)

Prolactin necessary for the maturation of the mammary gland, stimulates the formation and secretion of breast milk, inhibits the secretion of sex hormones.

luteinizing hormone promotes the production of the female sex hormone progesterone. Together with it, it supports ovulation and the second phase of the menstrual cycle.

Follicle stimulating hormone regulates the work of the ovaries: stimulates the growth and maturation of eggs, promotes the synthesis of estrogens.

ovaries

Estradiol The most active female sex hormone is estrogen.

• improves skin and hair condition
• stimulates memory
• strengthens bone tissue
• protects against atherosclerosis
• improves mood

Progesterone helps to maintain a regular menstrual cycle and maintain pregnancy in the first trimester.

Prolactin

In menstruating women - 130-540 mcU / ml. In women in menopause - 107-290 mcU / ml.

• failure of the pituitary gland.

Prolactin

To determine the level of this hormone, it is important to do an analysis in the 1st and 2nd phases of the menstrual cycle strictly on an empty stomach and only in the morning. Immediately before taking blood, the patient should be at rest for about 30 minutes.

Prolactin is involved in ovulation, stimulates lactation after childbirth. Therefore, it can suppress the formation of FSH for "peaceful purposes" during pregnancy and for non-peaceful purposes in its absence. With an increased or decreased content of prolactin in the blood, the follicle may not develop, as a result of which the woman will not ovulate. The daily production of this hormone has a pulsating character. During sleep, its level rises. After awakening, the concentration of prolactin decreases sharply, reaching a minimum in the late morning hours. After noon, the level of the hormone increases. During the menstrual cycle, prolactin levels are higher during the luteal phase than during the follicular phase.

Follicle stimulating hormone

Normal serum concentration: The norm varies depending on the period of the menstrual cycle:

• In the follicular phase - 3-11mU / ml.
• In the middle of the cycle - 10-45 mU / ml.
• In the luteal phase - 1.5-7 mU / ml.

Possible causes of increased hormone levels:

• insufficiency of the function of the gonads of a genetic or autoimmune nature due to surgical or radiation treatment
• chronic alcoholism
• orchitis
• pituitary tumors that produce follicle-stimulating hormone
• period of menopause.

Possible causes of low hormone levels:

• failure of the pituitary or hypothalamus
• pregnancy.

FSH (follicle stimulating hormone)

luteinizing hormone

Normal serum concentration:

• In the follicular phase of the cycle - 2-14 mU / ml.
• In the middle of the cycle - 24-150 mU / ml.
• In the luteal phase - 2-17 mU / ml.

Possible causes of increased hormone levels:

• insufficiency of gonadal function
• polycystic ovary syndrome
• pituitary tumors

Possible causes of low hormone levels:

• decreased function of the pituitary or hypothalamus
• anorexia nervosa.

LH (luteinizing hormone)

The secretion of luteinizing hormone is pulsatile and depends in women on the phase of the menstrual cycle. In the cycle in women, the peak concentration of LH falls on ovulation, after which the level of the hormone falls and "keeps" the entire luteal phase at lower values ​​than in the follicular phase. This is necessary in order for the corpus luteum to function in the ovary. In women, the concentration of LH in the blood is maximum in the interval from 12 to 24 hours before ovulation and is maintained during the day, reaching a concentration 10 times higher compared to the non-ovulatory period. During pregnancy, the concentration of LH decreases.

During the examination for infertility, it is important to monitor the ratio of LH and FSH. Normally, before the onset of menstruation, it is 1, a year after the onset of menstruation - from 1 to 1.5, in the period from two years after the onset of menstruation and before menopause - from 1.5 to 2.

Estradiol

Normal serum concentration:

• In the follicular phase - 110-330 pmol / l.
• In the middle of the cycle - 477-1174 pmol / l.
• In the luteal phase - 257-734 pmol / l.

Possible causes of increased hormone levels:

• ovarian or adrenal tumors that provoke estradiol
• cirrhosis of the liver
• thyrotoxicosis
• taking oral contraceptives
• pregnancy.

Possible causes of low hormone levels:

• ovarian failure, infertility
• taking certain contraceptive drugs.

Estradiol

A necessary condition for the work of the hormone estradiol is its correct ratio to the level of testosterone.

Progesterone

Normal serum concentration: For each phase of the cycle and week of pregnancy, there are separate indicators of the norm. So, a sign of ovulation and the formation of a corpus luteum is a tenfold increase in progesterone levels.

Possible causes of increased hormone levels:

• congenital dysfunction of the adrenal cortex
• ovarian tumors
• corpus luteum cyst
• diabetes
• in pregnant women, progesterone levels are elevated with renal failure and Rh sensitization.

Possible causes of low hormone levels:

• lack of ovulation, insufficiency of the "yellow body" and, as a result, infertility
• threatened miscarriage in early pregnancy.

Progesterone

This hormone is important to check on the 19th-21st day of the menstrual cycle. Progesterone is a hormone produced by the corpus luteum and the placenta (during pregnancy). It prepares the endometrium of the uterus for the implantation of a fertilized egg, and after its implantation, it helps to maintain the pregnancy.

thyroxine

Normal serum concentration:

• The level of total thyroxin is 64-150 nmol / l, or 5-10 μg / 100 ml.
• The content of free thyroxine is 10-26 pmol / l, or 0.8-2.1 ng / 100 ml.

Possible causes of increased hormone levels:

• hyperthyroidism and thyrotoxicosis - diseases associated with excessive thyroid function
• obesity
• pregnancy
• excessive use of drugs containing thyroxine, which are prescribed for the treatment of goiter
• thyroid adenoma.

Possible causes of low hormone levels:

• hypothyroidism - decreased thyroid function
• insufficiency of the pituitary gland
• the level of free thyroxin in the norm may decrease in the last trimester.

T4 (Thyroxine total)

The concentration of T4 in the blood is higher than the concentration of T3. This hormone, by increasing the rate of basal metabolism, increases heat production and oxygen consumption by all tissues of the body, with the exception of the tissues of the brain, spleen and testicles.

Hormone levels in men and women normally remain relatively constant throughout life. However, in some areas, there is often a decrease in the activity of the thyroid gland, which can lead to serious deviations in one's own health and the health of the unborn child. The hormone thyroxine consists of a prohormone (also very active) - triiodothyronine. The amino acid tyrosine and the microelement iodine serve as substrates for the formation of thyrothyronine and thyroxine. The thyroid gland is extremely important for the normal functioning of any living being. Its main hormone thyroxine is the reins that restrain and skillfully control the galloping horse - our body, adjusting the speed, pace, rhythm of the "run of life" to the conditions of the momentary situation.

Thyroxine contains iodine in its composition, an element whose intake into the body is limited. But nature has made sure that the thyroid gland has the necessary supply of iodine in case, for some reason, there is a break in the supply of the body due to the lack of this element in food. To do this, there is a mechanism that allows you to extract iodine from the blood and create a supply of it for up to 10 weeks.

Unlike other hormones, thyroxine is extremely stable and effective when administered orally. The thyroid gland provides vital functions. She is a barometer of the weather in the body. Thyroxine is necessary for the normal functioning of all organs and systems.

Little iodine - the synthesis of thyroxine is reduced. Hypothyroidism occurs. As a consequence, cretinism in childhood and a disease called myxedema in adults.

excess iodine - increased production of thyroid hormone - rarely occurs due to excess iodine, since excess iodine is excreted by the kidneys if they work normally. The cause of hyperthyroidism is in most cases the pathology of the pituitary gland - increased production of thyroid-stimulating hormone (TSH), which accelerates the synthesis of thyroxine in the thyroid gland. Most often, this is a hereditary predisposition or a pituitary tumor, consisting of cells that produce TSH.

When the thyroid gland is removed in young individuals, it leads to stunting, mental changes, severe metabolic disorders, dysfunction of the gonads, changes in the composition of the blood, dry skin, and a decrease in immune protection against infections.

In adults, when the thyroid gland is removed, the described disorders develop more slowly, but qualitatively manifest themselves in the same way as in young ones.

Therefore, the thyroid gland is never completely removed.

In response to a lack of iodine, increased reproduction of thyroid cells occurs as a compensatory-adaptive process. The gland is trying to restore balance - to increase the production of the missing thyroxine by increasing the number of cells producing it. Sometimes it can “overdo it” and then a thyrotoxic goiter occurs - a disease that occurs with symptoms of increased thyroxine production - bulging eyes, palpitations, sweating, psycho-emotional disorders (Basedow's disease).

Triiodothyronine

Normal serum concentration:

• The concentration of total triiodothyronine is 1.2-2.8 nmol / l, or 65-190 ng / 100 ml.
• The content of free triiodothyronine is 3.4-8.0 pmol / l, or 0.25-0.52 ng / 100 ml, an average of 0.4 ng / 100 ml.

Possible causes of increased hormone levels:

• overactive thyroid
• thyrotoxicosis.

Possible causes of low hormone levels:

• decreased thyroid function, as a variant of the norm - in the third trimester of pregnancy.

T3 free (Triiodothyronine free)

T3 is produced by thyroid follicular cells under the control of thyroid-stimulating hormone (TSH). It is a precursor of the more active hormone T4, but has its own, although less pronounced than that of T4, action.

Blood for analysis is taken on an empty stomach. Immediately before taking blood, the patient should be at rest for about 30 minutes.

Thyroid-stimulating hormone

Normal serum concentration:

• 1-4 honey / ml.

Possible causes of increased hormone levels:

• primary hypothyroidism - a condition that reflects an insufficiency of thyroid function
• pituitary tumors that produce a lot of thyroid-stimulating hormone.

Possible causes of low hormone levels:

• thyrotoxicosis
• decreased function of the pituitary gland
• treatment with thyroid hormones.

TSH (thyroid stimulating hormone)

The level of this hormone should be checked on an empty stomach to rule out thyroid dysfunction.

Testosterone

This hormone can be tested in both men and women on any given day. Both spouses need testosterone, but it is a male sex hormone. In the female body, testosterone is secreted by the ovaries and adrenal glands. Exceeding the normal concentration of testosterone in a woman can cause irregular ovulation and early miscarriage, and the maximum concentration of testosterone is determined in the luteal phase and during the period of ovulation. A decrease in the concentration of testosterone in a man causes, ... correctly, a lack of male strength and a decrease in the quality of sperm.

DEA sulfate

This hormone is produced in the adrenal cortex. This hormone can be tested in both men and women on any given day. It is also needed by the body of both spouses, but in different proportions, because it is also a male sex hormone.

THYROID HORMONES affect, among other things, the formation of germ cells in both spouses and the course of pregnancy.

Antibodies to TSH

Determination of antibodies to TSH makes it possible to predict dysfunction of the thyroid gland. Available on any day of the menstrual cycle

Attention

Many hormones have a daily rhythm of secretion, and their release is associated with food intake. Therefore, it is very important to take tests in the morning, on an empty stomach, after an overnight fast - optimally from 8 to 9 in the morning. The level of hormones that regulate sexual function depends on the phases of the menstrual cycle. So, if there were no special instructions from the doctor, a blood test for estradiol, LH, FSH, progesterone and prolactin should be taken on the 5-7th day from the start of menstruation.

On the eve and on the day of blood donation, intense physical and psycho-emotional stress should be avoided. Do not donate blood when the temperature rises, against the background of infectious diseases. It is advisable to cancel all medications 7 to 10 days before taking an analysis for hormones. If this is not possible, be sure to tell your doctor about the medications you are taking and any concomitant illnesses, since many illnesses can affect the results of laboratory tests.

How were hormones discovered?

The first hormone to be discovered was secretin, a substance produced in the small intestine when food from the stomach reaches it.
Secretin was discovered by English physiologists William Bayliss and Ernest Starling in 1905. They also found that secretin is able to “travel” throughout the body through the blood and reach the pancreas, stimulating its work.

And in 1920, Canadians Frederick Banting and Charles Best isolated one of the most famous hormones, insulin, from the pancreas of animals.

Where are hormones produced?

The main part of the hormones is produced in the endocrine glands: the thyroid and parathyroid glands, the pituitary gland, the adrenal glands, the pancreas, the ovaries in women and the testicles in men.

There are also hormone-producing cells in the kidneys, liver, gastrointestinal tract, placenta, thymus in the neck, and the pineal gland in the brain.

What do hormones do?

Hormones cause changes in the functions of various organs in accordance with the requirements of the body.

So, they maintain the stability of the body, provide its responses to external and internal stimuli, and also control the development and growth of tissues and reproductive functions.

The control center for the overall coordination of hormone production is located in the hypothalamus, which is adjacent to the pituitary gland at the base of the brain.
Thyroid hormones determine the speed of chemical processes in the body.

Adrenal hormones prepare the body for stress – the “fight or flight” state.

Sex hormones - estrogen and testosterone - regulate reproductive functions.

How do hormones work?

Hormones are secreted by the endocrine glands and circulate freely in the blood, waiting to be detected by the so-called target cells.

Each such cell has a receptor that is activated only by a certain type of hormone, like a lock is activated by a key. After receiving such a “key”, a certain process is launched in the cell: for example, the activation of genes or the production of energy.

What are the hormones?

There are two types of hormones: steroids and peptides.

Steroids are produced by the adrenal glands and gonads from cholesterol. A typical adrenal hormone is the stress hormone cortisol, which activates all body systems in response to a potential threat.

Other steroids determine the physical development of the body from puberty to old age, as well as reproductive cycles.

Peptide hormones regulate mainly metabolism. They are made up of long chains of amino acids and the body needs protein to secrete them.

A typical example of peptide hormones is growth hormone, which helps the body burn fat and build muscle.

Another peptide hormone - insulin - starts the process of converting sugar into energy.

What is the endocrine system?

The endocrine gland system works together with the nervous system to form the neuroendocrine system.

This means that chemical messages can be transmitted to the appropriate parts of the body either through nerve impulses, through the bloodstream through hormones, or both.

The body reacts more slowly to the action of hormones than to the signals of nerve cells, but their effect lasts for a longer time.

The most important

Hormones are a kind of “keys” that trigger certain processes in “lock cells”. These substances are produced in the endocrine glands and regulate almost all processes in the body - from fat burning to reproduction.