Functions of hormones in the human body. Group II - cytosolic mechanism

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 by specialized endocrine cells, released into the internal environment of the body (blood, lymph) and exerting 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 carriers of information, they, like other signaling molecules, have high biological activity and cause responses in target cells in very low concentrations (10 -6 - 10 -12 M/l).

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

Table. Classification physiologically active substances

Properties of hormones

Hormones have a number of general properties. They are usually formed by specialized endocrine cells. Hormones have selectivity of 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 presented in the form of 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 on animals, as well as to use hormones obtained from animals to treat sick people.

There are three options for intercellular interaction using hormones:

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

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

• peptides (number of amino acids up to 100, for example 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 hormones, controlling the function of peripheral endocrine glands;
• hypothalamic hormones regulating the secretion of hormones by the pituitary gland.

Table. Types of hormone action

Hormones circulate in the blood in a free (active form) and bound (inactive form) state with plasma proteins or formed elements. Hormones have biological activity in a free state. Their content in the blood depends on the rate of secretion, the degree of binding, uptake and rate of metabolism in tissues (binding with specific receptors, destruction or inactivation in target cells or hepatocytes), removal in urine or bile.

Table. Physiologically active substances recently discovered

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

The effect of a hormone on a target cell is due to binding and 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 from target cells. Activation of the receptor by a 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. Hormones of a hydrophilic (lyiophobic) nature, for which the cell membrane is impermeable, interact with cell membrane receptors (1-TMS, 7-TMS and ligand-gated ion channels). They are catecholamines, melatonin, serotonin, hormones of protein-peptide nature.

Hormones of a hydrophobic (lipophilic) nature diffuse across the plasma membrane and bind to intracellular receptors. These receptors are divided into cytosolic (receptors of steroid hormones - gluco- and mineralocorticoids, androgens and progestins) and nuclear (receptors of thyroid iodine-containing hormones, calcitriol, estrogens, retinoic acid). Cytosolic and estrogen receptors are associated with heat shock proteins (HSPs), which prevents 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 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 protein synthesis in the cell and other processes.

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

Table 8.1. Intracellular mechanisms and pathways of hormone action

Hormones control a variety of 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 influence of hormones, activation or inhibition of the energy and plastic metabolism of cells, the synthesis of various substances, including protein substances (metabolic effect of hormones); changes in the rate of cell division, its differentiation (morphogenetic effect), 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 effect), etc.

Table. Distribution of the hormone in the blood

The rate of occurrence in the body and the duration of responses to the action of hormones depends on the type of stimulated receptors and the metabolic rate of the hormones themselves. Changes in physiological processes can be observed after several tens of seconds and last for a short time when stimulating plasma membrane receptors (for example, vasoconstriction and an increase in blood pressure under the influence of adrenaline) or observed after several tens of minutes and lasting for hours when stimulating 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. Duration 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 effect 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 launched 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 norepinephrine can simultaneously act on the smooth myocyte of the vascular wall, summing up their vasoconstrictor effect. The vasoconstrictor effect of vasopressin can be eliminated or weakened by a simultaneous effect on smooth myocytes vascular wall bradykinin or nitric oxide.

Regulation of hormone formation and secretion

Regulation of hormone formation and secretion is one of the most important functions and nervous systems of the body. Among the mechanisms regulating the formation and secretion of hormones, the influence of the central nervous system, “triple” hormones, the influence of the concentration of hormones in the blood through negative feedback channels, the influence of the final effects of hormones on their secretion, the influence of circadian and other rhythms are distinguished.

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 receipt of nerve impulses from various areas of the central nervous system. These cells have a unique ability to excite 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 psycho-emotional 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.

The 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 the secretion of insulin 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 pituitary hormones 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 got their name because of their ability to bind (have affinity) with receptors of 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 - adrenocorticotropic hormone (ACHT). Tropic hormones to the endocrine cells of the gonads are called: lutropin or luteinizing hormone (LH) - to Leydig cells, 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. For example, TSH increases in thyroid gland blood flow, activates metabolic processes in thyrocytes, their capture of iodine from the blood, 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 under the influence of hypothalamic thyrotropin-releasing hormone (TRH) the secretion of TSH increases, then the latter will bind not only to the receptors of thyrsocytes, but also to the receptors of the neurosecretory cells of the hypothalamus. In the thyroid gland, TSH stimulates the formation of thyroid hormones, and 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, 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 hypothalamic hormones 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 set of glandular cells of the pituitary gland, hypothalamus and peripheral endocrine glands and the mechanisms of their mutual influence on each other were called the pituitary-hypothalamus-endocrine gland systems or axes. The systems (axes) are distinguished: pituitary gland - hypothalamus - thyroid gland; pituitary gland - hypothalamus - adrenal cortex; pituitary gland - hypothalamus - gonads.

Impact 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. When the blood glucose level increases, insulin secretion is stimulated, and when it decreases, glucagon secretion is stimulated. These hormones inhibit each other's secretion through a paracrine mechanism. When the level of Ca 2+ ions in the blood increases, the secretion of calcitonin is stimulated, and when it decreases, the secretion of parathyrin is stimulated. Direct influence concentration of substances on the secretion of hormones that control their levels is rapid and effective way maintaining the concentration of these substances in the blood.

Among the mechanisms under consideration for the regulation of hormone secretion and their final effects, one can note the regulation of secretion antidiuretic hormone(ADH) cells of the posterior hypothalamus. The secretion of this hormone is stimulated by an increase in osmotic pressure blood, for example due to fluid loss. A decrease in diuresis and fluid retention in the body under the influence 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.

The influence of circadian and other rhythms on the secretion of hormones takes place in the hypothalamus, adrenal glands, gonads, and 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 levels of melatonin are recorded at night. The influence of the lunar cycle on the secretion of sex hormones in women is well known.

Determination 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 cyclical, pulsating nature. The frequency of secretion is from 5-10 minutes to 24 hours or more (the common rhythm is about 1 hour).

Bound form of the hormone- formation of reversible, non-covalently bonded complexes of hormones 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 transport protein. For example, 90% of cortisol, 98% of testosterone and estradiol, 96% of triiodothyronine and 99% of thyroxine are bound 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 pool of free hormone.

Free form of the hormone- a physiologically active substance in the blood plasma in a state not bound to protein, capable of interacting with receptors. The bound form of the hormone is in dynamic equilibrium with a 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 hormone metabolism (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 - from 30 minutes to several days.

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

Organ specificity of the hormone action - responses of organs and tissues to physiologically active substances; they are strictly specific and cannot be caused 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 loop - 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 loop is an interaction within an endocrine gland in which the release of a hormone influences the processes of secretion and release of itself and other hormones from this 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, causing stimulation and the occurrence of a peak in 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, insulin.

Insulin- a protein substance produced in the 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 promote the breakdown 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, increasing the intensity of basal metabolism, heat production, affecting the growth and differentiation of tissues.

Glucagon - a polypeptide produced in the α-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 - actual corticosteroid hormones that have a specific physiological effect.

Catecholamines - derivatives of pyrocatechol, actively involved in physiological processes in the body of animals and humans. Catecholamines include adrenaline, norepinephrine and dopamine.

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

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

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

Regulatory peptides — high molecular weight 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 are called polypeptides, and over 50 are called proteins.

Antihormone- a protective substance produced by the body during prolonged administration of protein hormonal drugs. The formation of an antihormone is an immunological reaction to the introduction of a foreign protein from the outside. The body does not produce antihormones in relation to its own hormones. 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 close in structure to hormones and enter into competitive, antagonistic relationships with them. Antimetabolites of hormones are capable of taking their place in physiological processes occurring in the body or blocking hormonal receptors.

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

Neurohormone- a physiologically active substance produced by nerve cells.

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.

There are special substances in the human body - hormones, which participate in various chemical processes of a harmonious system and are a kind of impetus for the activity of certain organs. Why is the role of hormones so important for both women and men? What can an imbalance in hormone secretion lead to? To answer these questions, you need to understand what hormones are?

General information about hormones

Reference materials presented on Wikipedia characterize human hormones as “biologically active substances of organic nature produced in the cells of the endocrine glands.” After production in a particular gland, hormones enter the bloodstream and in a free flow or, by binding to proteins, reach the target, more precisely, the cells in a specific organ.

The entry of hormones into target cells serves as an impetus for a certain chemical reaction, for example, sex hormones form sexual characteristics in adolescence, or prepare female body to conception and gestation.

The body produces not one specific type of hormone, but a large variety of hormones that have a specific function.

Hormones are not a definite constant, because the concentration of hormones is constantly changing under the influence of internal and external processes.

The gland secretes a specific hormone and releases it into the blood. The hormone reaches the desired point, performs its function and is eliminated from the body through various channels. If a malfunction occurs in the endocrine gland or in another part of the body, the concentration of the hormone is also disrupted, which cannot but affect general work the whole body. Hence mood swings, weakness, nervousness, metabolic disorders, weakened potency, memory loss and much more.

The term itself "hormones", translated from Greek language It has literal translation“to excite or motivate,” that is, to be the main mechanism for launching vital systems that cannot be active on their own. The influence of hormones can be compared to an impulse transmitted in the nervous system from one neuron to another. Only the hormonal signal goes through the blood.

The main generators of hormones are the following glands of the human body:

• Pituitary - an appendage of the brain, a gland that is small in size, but has a large impact on the processes of growth, metabolism and formation reproductive system. It is here that hormones are produced that stimulate these processes. The gland is the center endocrine system, which includes glands that secrete other important hormones.
• Hypothalamus - medulla, a gland that regulates the formation of most hormones in the body.
• Thyroid - one of the components of the endocrine system glands. Despite its small weight and size, it occupies one of the main positions in the smooth functioning of the entire body and secretion important hormones.
• Adrenal glands - a paired gland that is part of the body’s endocrine system and produces both female and male hormones.
• Pancreas produces hormones that stimulate the gastrointestinal tract and participate in various metabolic processes in the body, for example, hormones that regulate glucose levels in the body.
• Male testicles and female ovaries - two types of endocrine glands that produce hormones that affect sexual and reproductive functions in the body.

In addition to the endocrine glands, the kidneys, liver, placenta during pregnancy, the thymus and pineal glands take part in the formation of hormones.

There are many hormones produced in the body, and not all types of hormones and their participation in chemical processes have yet been studied. Scientists continue to study the relationship various diseases, psychological manifestations with instability of hormone levels.

Classification of hormones

To systematize the hormones discovered and studied by specialists, it was decided to introduce a classification of hormones according to their chemical formula, place of secretion and purpose. The sources of hormone formation in the human body are the glands listed in the first chapter.

Now we need to consider the groups of hormones according to chemical composition:

Having considered the classification hormones by chemical composition and place of their secretion, the biological functions of hormones in the body, which are confirmed by scientific research, should be studied.

The table allows you to systematize the data for clarity:

In addition to the listed functions, many hormones are universal and perform different roles. For example:

• The main function of the hormone adrenaline - is the regulation of muscle contraction. In addition, the hormone is involved in stabilizing blood pressure and carbohydrate metabolism.
• The main role of estrogen (female hormone) - control reproductive function. In addition, this substance is involved in lipid metabolism and blood clotting.

But the entire list of functions of hormones in the human body has not yet been fully studied and the table presented can be expanded with new items over time.

What are the different groups of hormones responsible for in the human body?

Having studied in detail what hormones are and which glands generate their secretion, you need to understand what processes work smoothly if the level of active substances is normal:

1. From the moment of conception hormones control body growth and weight gain. The division of each cell, breakdown and disposal is under the strict control of certain hormones of the endocrine system.
2. Strength or weakness of the immune system- this is the influence of certain hormones. For example, a failure in the secretion of the parathyroid gland, which forms parathyroid hormones, leads to weakening of muscles, disturbances in the gastrointestinal tract, of cardio-vascular system. This, in turn, creates favorable conditions for the attack of viruses or bacteria, which are difficult for a weakened body to fight.
3. Any metabolic processes are carried out due to the sufficient content of certain hormones in the body (insulin regulates the conversion of glucose into energy).
4. Endocrine glands with sufficient hormone production stabilize a person’s psycho-emotional state. When hormones are imbalanced, mental and emotional stability disorders occur. This is clearly expressed in women, especially with changes in hormonal levels during menstrual cycle or menopause.
5. Physical activity and stress do not lead to negative consequences if hormonal background within normal limits. Sometimes a person himself does not understand how he coped with some extreme situation, and this activated the reserves of hormones, which the endocrine glands released into the blood in sufficient quantities.
6. Sleep and the ability to relax also depend on the production of a certain secretion by the glands. Hormone melatonin is responsible for sleep quality. It is also considered the hormone of youth if a person follows a sleep schedule and there is no reason for insomnia. If the level of cortisol (stress and panic hormone) in the body is increased, then the quality of sleep is disrupted, which leads to serious pathologies.
7. The feeling of hunger or satiety is the work of special hormones, an imbalance of which can lead to obesity or anorexia.
8. The interest of a man and a woman in each other is also controlled by hormones secreted endocrine glands.

The concentration of certain hormones changes throughout a person’s life. If there are no factors that reduce or increase the level of important hormones relative to the norm, then all processes in the body go uninterrupted, the person feels strength, energy and is capable of much.

Disturbances in the secretion of even one type of hormone destabilize the functioning of the body and gradually lead to a number of serious diseases, the source of which is sometimes difficult to get to the bottom of.

The role of hormones and the performance of the glands that produce these substances have great importance for stable functioning of the body and human sensations.

If internal dissonance arises, it immediately affects the quality of life. You need to pay attention to your feelings so as not to miss hormonal surges.

Hormones need to be kept under control

In men, the production of hormones by the endocrine glands is more stable than in women. This is provided by nature and psychological stability.

Women are more impulsive, more changes occur inside, because internal organs and glands must perform the main function - reproductive.

Female hormones affect mood, especially during menstruation or menopause. Appearance also largely depends on the stability of the functioning of the endocrine glands, which are responsible for the production of hormones of the thyroid gland, adrenal glands, ovaries, and placenta.

When the following symptoms, pointing to hormonal disbalance or pathology of one of the hormonal glands, you should contact the clinic for a comprehensive examination:

• Weakness in the body, apathy towards life.
• Disruptions in the menstrual cycle may indicate problems in the thyroid gland and the production of sex hormones. The problem can develop into cancer.
• Cramps or numbness in the legs and arms.
• Headaches, extraneous sounds in the ears.
• Pressure and temperature surges.
• A feeling of dullness, forgetfulness, disorientation in space and time can signal problems in the pituitary gland or hypothalamus, which are glands that secrete important hormones.
• Hair growth in unexpected places, for example, women develop facial hair, which may be the cause of a malfunction in the secretion of female and male hormones, or pathologies in the thyroid gland, adrenal glands, testes or ovaries.
• Mood swings, depression.
• Increased sweating, tremors of extremities.

The list of disorders that arise due to an imbalance in the secretion of hormones by one or another gland can be listed for a long time. But I would like to draw your attention to the fact that with any symptoms of instability in the functioning of the body, you need to pay attention to yourself and find the cause. A deficiency or excess of a hormone can be compensated for by special therapy or diet, if there are no serious disturbances in the functioning of the glands responsible for the stability of the balance of hormones.

There is a different list of laboratory tests to determine the level of a specific hormone in the body. The performance of the thyroid gland, pancreas, parathyroid gland, adrenal glands and other glands that are part of the secretion system of important hormones can be analyzed by hardware examination. Hormones of the thyroid gland, the main organ of the endocrine system, can be analyzed in any laboratory.

Self-medication if you suspect a hormonal imbalance or a pathology in the endocrine glands is dangerous, because time will be lost and the situation will become critical.

The word “hormones” today refers to several groups of biologically active substances. First of all, these are chemical substances that are formed in special cells and have a powerful effect on all development processes of a living organism. In humans, most of these substances are synthesized in the endocrine glands and distributed through the blood throughout the body. Invertebrate animals and even plants have their own hormones. A separate group is medical supplies, which are made on the basis of such substances or having a similar effect.

What are hormones

Hormones are substances that are synthesized (primarily) in the endocrine glands. They are released into the blood, where they bind to special target cells, penetrate all organs and tissues of our body and from there regulate all kinds of metabolic processes and physiological functions. Some hormones are also synthesized in the exocrine glands. These are hormones of the kidneys, prostate gland, stomach, intestines, etc.

Scientists became interested in these unusual substances and their effect on the body back in the late XIX century, when the British doctor Thomas Addison described the symptoms of a strange disease caused by. The most clear symptoms such a disease - eating disorders, eternal irritation and anger and dark spots on the skin - hyperpigmentation. The disease later received the name of its “discoverer,” but the term “hormone” itself appeared only in 1905.

The mechanism of action of hormones is quite simple. First, an external or internal stimulus appears that acts on a specific receptor in our body. The nervous system immediately reacts to this, sends a signal to the hypothalamus, and it gives a command to the pituitary gland. The pituitary gland begins to secrete tropic hormones and sends them to various endocrine glands, which in turn produce their own hormones. Then these substances are released into the blood, bind to certain cells and cause certain reactions in the body.

Human hormones are responsible for the following processes:

• control of our mood and emotions;
• stimulation or inhibition of growth;
• ensuring apoptosis (the natural process of cell death, a kind of natural selection);
• change life cycles (puberty, childbirth, menopause);
• regulation of the immune system;
• sexual desire;
• reproductive function;
• regulation of metabolism, etc.

Types of hormone classifications

Modern science knows more than 100 hormones, their chemical nature and the mechanism of action have been studied in sufficient detail. But, despite this, a general nomenclature for these biologically active substances has not yet appeared.

Today there are 4 main typologies of hormones: according to the specific gland where they are synthesized, according to biological functions, as well as functional and chemical classification of hormones.

1. By the gland that produces hormonal substances:

• adrenal hormones;
• thyroid gland;
• parathyroid glands;
• pituitary gland;
• pancreas;
• gonads, etc.

2. By chemical structure:

• steroids (corticosteroids and sex hormones);
• fatty acid derivatives (prostaglandins);
• amino acid derivatives (adrenaline and norepinephrine, melatonin, histamine, etc.);
• protein-peptide hormones.

Protein-peptide substances are divided into simple proteins (insulin, prolactin, etc.), complex proteins (thyrotropin, lutropin, etc.), as well as polypeptides (oxytocin, vasopressin, peptide gastrointestinal hormones, etc.).

3. By biological functions:

• metabolism of carbohydrates, fats, amino acids (cortisol, insulin, adrenaline, etc.);
• calcium and phosphate metabolism (calcitriol, calcitonin)
• control water-salt metabolism(aldosterone, etc.);
• synthesis and production of hormones of intrasecretory glands (hormones of the hypothalamus and tropic hormones of the pituitary gland);
• provision and control of reproductive function (testosterone, estradiol);
• changes in metabolism in cells where hormones are formed (histamine, gastrin, secretin, somatostatin, etc.).

4. Functional classification of hormonal substances:

• effector (act specifically on the target organ);
• tropic hormones of the pituitary gland (control the production of effector substances);
• releasing hormones of the hypothalamus (their task is the synthesis of pituitary hormones, mainly tropic ones).

Hormone table

Each hormone has several names - the full chemical name indicates its structure, and the short working name can indicate the source where the substance is synthesized or its function. The full and well-known names of the substances, their place of synthesis and mechanism of action are indicated in the following table.

Synthetic hormones

The unique effect of hormones on the human body, their ability to regulate the processes of growth, metabolism, puberty, and influence the conception and bearing of a child, prompted scientists to create synthetic hormones. Today, such substances are used mainly for the development of medical drugs.

Synthetic hormones may contain substances from the following groups.

• Hormone extracts obtained from the endocrine glands of slaughtered livestock.
• Artificial (synthetic) substances that are identical in structure and function to conventional hormones.
• Chemical synthetic compounds, which in structure are very close to human hormones and have a clear hormonal effect.
• Phytohormones – herbal preparations, which exhibit hormonal activity when they enter the body.

Also, all such drugs are divided into several types depending on their origin and medicinal purposes. These are preparations of thyroid and pancreatic hormones, adrenal glands, sex hormones, etc.

There are several types of hormonal therapy: replacement, stimulating and blocking. Replacement therapy involves taking a course of hormones if the body for some reason does not synthesize them itself. Stimulating therapy is designed to activate vital processes for which hormones are usually responsible, and blocking therapy is used to suppress the hyperfunction of the endocrine glands.

Also, drugs can be used to treat diseases that are not caused by dysfunction of the endocrine system. These are inflammations, eczema, psoriasis, asthma, autoimmune diseases - diseases caused by the fact that the immune system goes crazy and unexpectedly attacks its own cells.

Plant hormones

Plant hormones (or phytohormones) are biologically active substances that are formed inside a plant. Such hormones have regulatory functions similar to the action of classical hormones (seed germination, plant growth, fruit ripening, etc.).

Plants do not have special organs that synthesize phytohormones, but the pattern of action of these substances is very similar to that of humans: first, plant hormones are formed in one part of the plant, then move to another. The classification of plant hormones includes 5 main groups.

1. Cytokinins. They stimulate plant growth through cell division and ensure the correct shape and structure of its various parts.
2. Auxins. Activate the growth of roots and fruits by stretching plant cells.
3. Abscisins. They inhibit cell growth and are responsible for the state of plant dormancy.
4. Ethylene. Regulates the ripening of fruits and the opening of buds and ensures communication between plants. Ethylene can also be called adrenaline for plants - it is actively involved in the response to biotic and abiotic stress.
5. Gibberellins. They stimulate the growth of the primary root of the grain embryo and control its further germination.

Also, phytohormones sometimes include B vitamins, primarily thiamine, pyridoxine and niacin.

Phytohormones are actively used in agriculture to enhance plant growth, as well as to create female hormonal preparations during menopause. IN natural form plant hormones are found in flax seeds, nuts, bran, legumes, cabbage, soy, etc.

Another popular area of ​​application of plant hormones is cosmetics. In the middle of the last century, Western scientists experimented with adding natural, human hormones to cosmetics, but today such experiments are prohibited by law in both Russia and the USA. But phytohormones are very actively used in women's cosmetics for any skin - both young and mature.

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

Classification of hormones

Depending on the chemical structure, secrete these types of hormones. The protein-peptide group combines the secretions of glands such 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). The hormones of the first two groups are primarily 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 secretion 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 structural element, triggering the synthesis of so-called intermediary molecules. It is typical that hydrophilic hormones are transported through the bloodstream, while lipophilic hormones bind to its proteins and are transported that way.

Human endocrine system

This is the name given to the totality of all glands and organs in the human body that secrete special biologically active elements - hormones. The endocrine system is responsible for many processes, while providing normal development body. She's in control 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, and hypothalamus. This 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
).

Tissue hormones, their types and functions

This type of hormone is produced in the tissues of the body and their effect is usually local. Sometimes such hormones can enter the blood. Histamine is a substance that plays a large role in the occurrence of allergic reactions. In the active state, it causes dilation of blood vessels and increases their permeability. Histamine also promotes contractions of the intestinal muscles and can cause spasms in the bronchi. Serotonin has the following effect: blood vessels narrow, their permeability decreases. It is also called the hormone of happiness. If its production is normal, a person has 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 hormone. Their types and functions are as follows. Nanopeptide, kallidin, T-kinin, bradykinin (lowers blood pressure) - all of them, when they enter the blood, cause symptoms inflammatory process. These hormones are involved in Another category of biologically active tissue secretions - prostaglandins. They affect the smooth muscles of organs and reduce the secretion of gastric juice. Substances such as kelons 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 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 into the body 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 entire organism and 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 fatigue person, lethargy, all metabolic processes slow down. If they are produced in excess, then excessive activity and excitability can be observed.

Analysis of hormones produced by the thyroid gland

If a person experiences changes such as weight fluctuations (sudden weight gain or loss), problems with sexual attraction, cessation of menstruation, developmental delay (psychological) in children, then a blood test for hormones produced by the thyroid gland is required. To pass it, you must prepare in a special way. It is best to limit any physical activity the night before the test. It is also worth eliminating alcohol, coffee, tobacco (at least 24 hours before). Blood sampling occurs in the morning, on an empty stomach. Thyroid hormones can be either bound or free. Therefore, during the studies, the amount of free thyroxine, free triiodothyronine, thyrotropin, as well as the level of antibodies to thyroid peroxidase and thyroglobulin are determined. Typically, the study takes one day. Depending on the results obtained, we can talk about one or another disease.

and her secrets

On the posterior surface of the thyroid gland there 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 the person, the gland can be of a reticular type, alveolar, or in the form of a solid mass. It synthesizes parathyroid hormone, which, like calcitonin, takes part in calcium metabolism. It also influences skeletal system, intestines, kidneys. If the production of parathyroid hormone is impaired, then mental disorders, bone problems, and calcification are possible internal organs, vessels. With hypoparateriosis, muscle cramps appear, the heart rate increases, 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 that are located on 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. Hormones of this type also control glucose levels. The adrenal medulla synthesizes adrenaline and norepinephrine. They are often produced during strong emotional outbursts (fear, danger). When these hormones enter the blood, it increases arterial pressure, the heart rate increases, the excitability of the receptors of the organs of vision and hearing increases. Thus, the body prepares for the need to endure stressful situation. The adrenal glands produce glucocorticoid hormones (cortisol), which regulate carbohydrate metabolism. Their concentration depends on the time of day: the maximum amount of cortisol is observed at approximately 6 am. Mineralocorticoid hormones (aldosterone) regulate salt metabolism. Thanks to them, fluid is retained in the body. The adrenal glands also secrete androgens such as androstenedione and dehydroepiandrosterone (DHEA). They regulate the functioning of the sebaceous glands and form libido. A blood test for adrenal hormones examines the level of DHEA. Its high content may indicate the presence of gland tumors. In addition, an excess of this hormone leads to severe consequences during pregnancy (miscarriage, malnutrition of the child, problems with the placenta). If there are complaints about increased hair growth, early 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 digestive process, it also produces hormones that are essential for the normal functioning of the body. All of them enter directly into the human blood. This organ produces the following types of hormones: insulin, c-peptide, glucagon. The main function of insulin is to regulate sugar levels. If the processes of its synthesis are disrupted, the development of diabetes mellitus. Insulin also affects the production of active substances in the gastrointestinal tract and the synthesis of estrogen. It can be found in the body in free and bound form. If the amount of insulin is insufficient, the process of converting glucose into fat and glycogen is disrupted. At the same time, toxins (for example, acetone) can accumulate in the body. Glucagon is also extremely necessary element for our body. It activates the process of fat breakdown and helps increase blood glucose levels. It also helps reduce the level of calcium and phosphorus in the blood. The types of action of pancreatic hormones are closely interrelated. Their combined influence ensures optimal glucose levels.

Functions of pituitary hormones

The pituitary gland is an endocrine gland that consists of an anterior and posterior lobe, as well as a small area between them. Weighs this body Only 0.5 grams, but it performs quite important functions. The pituitary gland synthesizes the following types human hormones. Adrenocorticotropic hubbub stimulates the adrenal cortex. It also affects the formation of melanin. affects the proper functioning of the reproductive system. Thanks to it, ovulation is stimulated and androgens are produced. Thyroid-stimulating 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 and lipid breakdown. This hormone is responsible for the normal physical development of the human body. Increasing 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 and to increase weight in athletes. Prolactin is the main hormone responsible for milk production in women. Also, thanks to its production, it does not occur during breastfeeding. next pregnancy. Melanotropin is produced in the middle lobe. The posterior lobe produces types of human hormones such as oxytocin and vasopressin. The first promotes contraction of the uterus, colostrum is produced. Vasopressin stimulates the muscles of organs such as the intestines, uterus, and blood vessels.

Sex glands

The ovaries and testes produce sex hormones. Their types are as follows. First of all, they are divided into women's and men's. However, they can also be present in small quantities in the opposite sex. Types of testosterone, androsterone, dihydrotestosterone, androstenediol. All of them ensure the development of both primary and secondary sexual characteristics. It should be noted that their level does not tolerate such fluctuations compared to women's secrets. Thanks to testosterone, seminal fluid is produced and attraction to the opposite sex is stimulated. The muscles and skeleton also develop in a special way, and a characteristic male timbre of voice appears. Other types of steroid hormones (in particular, dihydrotestosterone) provide male behavior, as well as a characteristic appearance: hair growth in certain areas, body structure. Kinds female hormones are: progesterone, estrogen, prolactin (produced by the pituitary gland).
Progesterone is produced by the corpus luteum. This gland is formed after ovulation. Performs the following functions: promotes the growth of the uterus, provides the opportunity for the egg (fertilized) to attach to its cavity. Progesterone prepares a woman for pregnancy and also contributes to bearing a child. If the amount of hormone is insufficient, the menstrual cycle will be disrupted and bleeding may occur. Low progesterone levels also affect emotional state: as a rule, a woman suffers from sharp changes moods. An increased level of the hormone may indicate either pregnancy or a tumor process. Estrogens - special types hormones in women. These include estradiol, estrone, estriol. These substances are responsible for the formation female type figures, increase skin tone and elasticity. In addition, hormones of this type contribute normal course menses. 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 estrogen levels are insufficient, there is male type hair growth, the skin ages earlier, excess weight accumulates in the abdomen and hips, bones become more fragile.

Blood test for sex hormones

Types of hormone tests include blood testing to determine whether it contains sexual secretions. It is prescribed if the following disorders occur: 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 or infertility. Blood must be donated in the morning; you cannot eat beforehand. The day before, you should give up tobacco and alcohol, physical activity. A woman needs to choose the right time for testing, since hormone levels depend on the day of the menstrual cycle. Several indicators are examined simultaneously. 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, it is responsible for follicle maturation, ovulation, and the formation of glands such as corpus luteum. If it is impossible to get pregnant, the indicators of follicle-stimulating and luteinizing hormone in combination are examined. A blood test is also performed to determine the presence of a certain amount of prolactin. If there are deviations from the norm, the onset of ovulation becomes more difficult. The blood is also tested for testosterone. It is present in the body of both sexes. If its levels are lower than normal in men, then the quality of sperm deteriorates. It also negatively affects potency. In women, excess testosterone can cause miscarriage.

Hormones are special chemical messengers that regulate the functioning of the body. They are secreted by endocrine glands and travel through the bloodstream, stimulating certain cells.

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

This name accurately reflects the functions of hormones as catalysts for chemical processes at the cellular level.

How were hormones discovered?

The first hormone discovered was secretin- a substance that is produced in small intestine when food reaches it from the stomach.

Secretin was discovered by English physiologists William Bayliss and Ernest Starling in 1905. They found that secretin is able to “travel” through the blood throughout the body and reach the pancreas, stimulating its work.

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

Where are hormones produced?

The main part of 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 testes in men.

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

What do hormones do?

Hormones cause changes in function various organs according to the body's requirements.

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

The control center for overall coordination of hormone production is located in hypothalamus, which is adjacent to the pituitary gland at the base of the brain.

Thyroid hormones determine the rate of chemical processes in the body.

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

Sex hormones– estrogen and testosterone – regulate reproductive functions.

How do hormones work?

Hormones are secreted by 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 with a key. After receiving such a “key,” a certain process starts in the cell: for example, gene activation or energy production.

What hormones are there?

There are two types of hormones: steroids and peptides.

Steroids Produced by the adrenal glands and gonads from cholesterol. A typical adrenal hormone is 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 mainly regulate metabolism. They consist of long chains of amino acids and for their secretion the body needs a supply of protein.

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

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 using hormones, or both.

The body reacts to the action of hormones more slowly than to signals from nerve cells, but their effects last longer.

The most important

Gomones 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.