What substances can be represented by human hormones. Hormones responsible for human health

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

The term “hormone” itself comes from the Greek word for “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 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 from the pancreas of animals - insulin.

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 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 – 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 determined 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?

Hormones are of two types: steroids and peptides.

Steroids produced by the adrenal glands and gonads from cholesterol. Typical adrenal hormone 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 a 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

Gomons are a kind of “keys” that launch 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.

1. What substances are called hormones? What are their main properties?

Hormones are chemical compounds with high biological activity, secreted by endocrine glands.

Properties of hormones:

• produced in small quantities
• the distant nature of the action (the organs and systems that hormones act on are located far from the place of their formation, therefore hormones are carried throughout the body with the bloodstream);
• remain active for a long time;
• strict specificity of action;
• high biological activity;
• regulate metabolic processes, ensure the constancy of the composition of the environment, affect the growth and development of organs, provide the body's response to the external environment.

According to their chemical nature, hormones are divided into three groups: polypeptides and proteins (insulin); amino acids and their derivatives (thyroxine, adrenaline); steroids (sex hormones).

If an increased amount of hormones is formed and released into the blood, this is hyperfunction. If the amount of hormones produced and released into the blood decreases, then this is hypofunction.

2. What glands produce hormones? Name them. What effect do the hormones of these glands have on the body?

The thyroid gland is located on the neck, in front of the larynx, produces hormones rich in iodine - thyroxine, etc. They stimulate the body's metabolism. The level of oxygen consumption by the organs and tissues of the body depends on their amount in the blood, i.e. thyroid hormones stimulate oxidative processes in cells. In addition, they regulate water, protein, fat, carbohydrate, mineral metabolism, growth and development of the body. They have an effect on the functions of the central nervous system and higher nervous activity. Lack of the hormone in childhood leads to cretinism (growth, sexual and mental development is delayed, body proportions are disturbed). With hypofunction in an adult, myxedema develops (decreased metabolism, obesity, lowering body temperature, apathy). With hyperfunction in adults, Graves' disease occurs (enlargement of the thyroid gland, development of goiter, bulging eyes, increased metabolism, increased excitability of the nervous system).

Adrenals. Small bodies above the kidneys. They consist of two layers: outer (cortical) and inner (brain). The outer substance produces hormones that regulate metabolism (sodium, potassium, proteins, carbohydrates, fats), and sex hormones (cause the development of secondary sexual characteristics). With insufficient function of the adrenal cortex, a disease develops, which is called bronze disease. The skin acquires a bronze color, there is increased fatigue, loss of appetite, nausea. With hyperfunction of the adrenal glands, an increase in the synthesis of sex hormones is noted. At the same time, secondary sexual characteristics change. For example, women get mustaches, beards, and so on.

The internal substance produces the hormones adrenaline and norepinephrine. Adrenaline accelerates the circulation of blood, increases the heart rate, mobilizes all the forces of the body in stressful situations, increases blood sugar (breaks down glycogen). The amount of adrenaline is under the control of the central nervous system, there is no shortage. In excess, it speeds up the work of the heart, constricts blood vessels. Norepinephrine slows down the heart rate.

Pancreas. It is located in the abdominal cavity of the body, below the stomach. It is a gland of mixed secretion, has excretory ducts and secretes enzymes involved in digestion. Individual cells of the pancreas secrete hormones into the blood. One group of cells produces the hormone glucagon, which promotes the conversion of liver glycogen into glucose, resulting in an increase in blood sugar levels. Other cells produce insulin. This is the only hormone that lowers blood sugar (promotes the synthesis of glycogen in liver cells). Insufficiency of pancreatic function develops diabetes mellitus. This raises the level of sugar in the blood. Carbohydrates are not stored in the body, but are excreted in the urine in the form of glucose.

The sex glands - the testes in men and the ovaries in women - also belong to the glands of mixed secretion. Due to the exocrine function, sperm and eggs are formed. Endocrine function is associated with the production of male and female sex hormones that regulate the development of secondary sexual characteristics. They influence the formation of the body, metabolism and sexual behavior. Androgens are produced in the testicles. They stimulate the development of secondary sexual characteristics characteristic of men (growth of a beard, mustache, muscle development, etc.), increase basal metabolism, and are necessary for the maturation of spermatozoa.

In the ovaries, female sex hormones are formed - estrogens, under the influence of which the formation of secondary sexual characteristics characteristic of women (body shape, development of the mammary glands, etc.) material from the site

Pituitary. It is located below the bridge of the brain and consists of three lobes: anterior, intermediate and posterior. The anterior lobe secretes growth hormone, which affects the growth of bones in length, accelerates metabolic processes, leads to increased growth, and an increase in body weight. The lack of a hormone is dwarfism, while the proportions of the body and mental development are not violated. Hyperfunction in childhood leads to gigantism (children have long limbs, they are not physically strong enough), in adults acromegaly occurs (the size of the hand, foot, front of the skull, nose, lips, chin increase). Hypofunction in adults leads to a change in metabolism: either to obesity or to a sharp weight loss.

The intermediate lobe of the pituitary gland secretes a hormone that affects skin pigmentation.

The posterior lobe is formed by nervous tissue. It does not synthesize hormones. Biologically active substances produced by the nuclei of the hypothalamus are transported to the posterior lobe of the pituitary gland. One of them selectively affects the contraction of the smooth muscles of the uterus and the secretion of the mammary glands. The other raises blood pressure and delays the excretion of urine. With a decrease in the amount of this substance, urination increases to 10-20 liters. per day. This disease is called diabetes insipidus.

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• what are hormones and what are their properties
• hormones briefly about them

What are hormones?

Hormones (from the Greek hormao - “set in motion”, “induce”) are biologically active substances that are formed mainly in the endocrine glands (endocrine glands) and have a regulatory effect on body functions.

Where are hormones formed?

Most hormones are produced in the endocrine glands. The table shows the main hormones of the human body.

How do hormones work?

Hormones act on body cells through target cell receptors. The binding of the hormone to the receptor leads to the formation of a signal inside the cell. This causes a certain biological effect. Hormones can target one or more different tissues.

What hormones are tested in men?

The "male" sex hormones are androgens.

"Female" sex hormones

The main "female" sex hormones are estrogen and progesterone.

What happens if hormone levels are too high or too low?

Violation of the functions of the endocrine system is manifested by a variety of disorders. For example, a lack of growth hormone in children is manifested by dwarfism, an excess of thyroid hormones - thyrotoxicosis, a lack of erythropoietin - anemia.

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 carriers of information, 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, estrogen, 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 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 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.

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 capture 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, they bind to the thyroid hormone receptors of 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 fast 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.

The human body is very complex. In addition to the main organs in the body, there are other equally important elements of the entire system. Hormones are one of these important elements. Since very often this or that disease is associated precisely with an increased or, on the contrary, underestimated in the body.

Let's figure out what hormones are, how they work, what their chemical composition is, what are the main types they have, what consequences can occur if they do not function properly, and how to get rid of pathologies that have arisen due to hormonal imbalance.

What are hormones

Human hormones are biologically active substances. What it is? These are chemicals that the human body contains, which have a very high activity with a small content. Where are they produced? They are formed and function inside the cells of the endocrine glands. These include:

• pituitary;
• hypothalamus;
• epiphysis;
• thyroid;
• parathyroid gland;
• thymus gland - thymus;
• pancreas;
• adrenal glands;
• sexual glands.

Some organs can also take part in the production of the hormone, such as: kidneys, liver, placenta in pregnant women, gastrointestinal tract and others. The hypothalamus, a small outgrowth of the main brain, coordinates the functioning of hormones (photo below).

Hormones are carried through the blood and regulate certain metabolic processes and the work of certain organs and systems. All hormones are special substances created by the cells of the body to affect other cells in the body.

The definition of "hormone" was used for the first time by W. Bayliss and E. Starling in their works in 1902 in England.

Causes and signs of hormone deficiency

Sometimes, due to the occurrence of various negative reasons, the stable and uninterrupted work of hormones can be disturbed. These unfortunate reasons include:

• transformations within a person due to age;
• diseases and infections;
• emotional interruptions;
• climate change;
• unfavorable environmental situation.

The male body is more stable in hormonal terms, unlike female individuals. Their hormonal background can periodically change both under the influence of the general causes listed above, and under the influence of processes that are unique to the female sex: menstruation, menopause, pregnancy, childbirth, lactation and other factors.

The following signs indicate that a hormone imbalance has arisen in the body:

• weakness;
• convulsions;
• headache and ringing in the ears;
• sweating.

In this way, hormones in body a person is an important component and an integral part of his functioning. The consequences of hormonal imbalance are disappointing, and treatment is long and expensive.

The role of hormones in human life

All hormones are undoubtedly very important for the normal functioning of the human body. They affect many processes occurring inside the human individual. These substances are inside people from the moment of birth until death.

Due to their presence, all people on earth have their own, different from others, growth and weight indicators. These substances affect the emotional component of the human individual. Also, over a long period, they control the natural order of increase and decrease of cells in human bodies. They coordinate the formation of immunity, stimulating it or suppressing it. They also put pressure on the order of metabolic processes.

With their help, the human body is easier to cope with physical exertion and any stressful moments. So, for example, thanks to adrenaline, a person in a difficult and dangerous situation feels a surge of strength.

Also, hormones to a large extent affect the body of a pregnant woman. Thus, with the help of hormones, the body prepares for successful delivery and care of the newborn, in particular, the establishment of lactation.

The very moment of conception and in general the entire function of reproduction also depends on the action of hormones. With an adequate content of these substances in the blood, sexual desire appears, and with a low and missing to the required minimum, libido decreases.

Classification and types of hormones in the table

The table shows the internal classification of hormones.

The following table contains the main types of hormones.

The main properties of hormones

Whatever the classification of hormones and their functions, they all have common features. The main properties of hormones:

• biological activity despite low concentration;
• action distance. If the hormone is formed in some cells, then this does not mean at all that it regulates these particular cells;
• limited action. Each hormone plays its strictly assigned role.

The mechanism of action of hormones

Types of hormones have an impact on the mechanism of their action. But in general, this action lies in the fact that hormones, being transported through the blood, reach the cells that are targets, penetrate into them and transmit a carrier signal from the body. In the cell at this moment there are changes associated with the received signal. Each specific hormone has its own specific cells located in the organs and tissues to which they aspire.

Some types of hormones attach to receptors that are contained inside the cell, in most cases, in the cytoplasm. These species include those that have lipophilic properties of hormones and hormones produced by the thyroid gland. Due to their lipid solubility, they easily and quickly penetrate into the cell to the cytoplasm and interact with receptors. But in water, they are difficult to dissolve, and therefore they have to attach to carrier proteins to move through the blood.

Other hormones can dissolve in water, so there is no need for them to attach to carrier proteins.

These substances affect cells and bodies at the moment of connection with neurons located inside the cell nucleus, as well as in the cytoplasm and on the membrane plane.

For their work, an intermediary link is needed, which provides a response from the cell. They are presented:

• cyclic adenosine monophosphate;
• inositol triphosphate;
• calcium ions.

That is why the lack of calcium in the body has an adverse effect on the hormones in the human body.

After the hormone has transmitted a signal, it breaks down. It can split in the following places:

• in the cell to which he moved;
• in blood;
• in the liver.

Or it can be excreted from the body with urine.

The chemical composition of hormones

According to the constituent elements of chemistry, four main groups of hormones can be distinguished. Among them:

1. steroids (cortisol, aldosterone and others);
2. consisting of proteins (insulin and others);
3. formed from amino acid compounds (adrenaline and others);
4. peptide (glucagon, thyrocalcitonin).

Steroids, at the same time, can be distinguished into hormones by sex and adrenal hormones. And the sexes are classified into: estrogen - female and androgens - male. Estrogen contains 18 carbon atoms in one molecule. As an example, consider estradiol, which has the following chemical formula: C18H24O2. Based on the molecular structure, the main features can be distinguished:

• in the molecular content, the presence of two hydroxyl groups is noted;
• according to the chemical structure, estradiol can be determined both to the group of alcohols and to the group of phenols.

Androgens are distinguished by their specific structure due to the presence in their composition of such a hydrocarbon molecule as androstane. The variety of androgens is represented by the following types: testosterone, androstenedione and others.

Name given to chemistry testosterone - seventeen-hydroxy-four-androsten-trione, a dihydrotestosterone - seventeen-hydroxyandrostane-trione.

According to the composition of testosterone, it can be concluded that this hormone is an unsaturated ketoalcohol, and dihydrotestosterone and androstenedione are obviously products of its hydrogenation.

From the name of androstenediol, information follows that it can be classified as a group of polyhydric alcohols. Also from the name you can draw a conclusion about the degree of its saturation.

Being a sex-determining hormone, progesterone and its derivatives, in the same way as estrogens, is a female-specific hormone and belongs to the C21 steroids.

Studying the structure of the progesterone molecule, it becomes clear that this hormone belongs to the group of ketones and that its molecule contains as many as two carbonyl groups. In addition to the hormones responsible for the development of sexual characteristics, steroids include the following hormones: cortisol, corticosterone and aldosterone.

If we compare the formula structures of the types presented above, then we can conclude that they are very similar. The similarity lies in the composition of the nucleus, which contains 4 carbo-cycles: 3 with six atoms and 1 with five.

The next group of hormones are amino acid derivatives. Their composition includes: thyroxine, epinephrine and norepinephrine.

Peptide hormones are more complex than others in their composition. One such hormone is vasopressin.

Vasopressin is a hormone formed in the pituitary gland, the value of the relative molecular weight of which is equal to one thousand eighty-four. In addition, in its structure it contains nine amino acid residues.

Glucagon, located in the pancreas, is also one of the types of peptide hormones. Its relative mass exceeds the relative mass of vasopressin by more than two times. It is 3485 units due to the fact that in its structure there are 29 amino acid residues.

Glucagon contains twenty-eight groups of peptides.

The structure of glucagon in all vertebrates is almost the same. Due to this, various preparations containing this hormone are created medically from the pancreas of animals. Artificial synthesis of this hormone in laboratory conditions is also possible.

A greater content of amino acid elements include protein hormones. In them, amino acid units are connected into one or more chains. For example, the insulin molecule consists of two polypeptide chains, which include 51 amino acid units. The chains themselves are connected by disulfide bridges. Human insulin has a relative molecular weight of five thousand eight hundred and seven units. This hormone has homeopathic significance for the development of genetic engineering. That is why it is produced artificially in the laboratory or transformed from the body of animals. For these purposes, it was necessary to determine the chemical structure of insulin.

Somatotropin is also a type of protein hormone. Its relative molecular weight is twenty one thousand five hundred units. A peptide chain consists of one hundred and ninety-one amino acid elements and two bridges. To date, the chemical structure of this hormone in the human body, bull and sheep has been determined.

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