Hormones are multi-structured organic substances that can affect the vital activity of the human body. Gonadotropic hormones affect the functioning of the reproductive system. They are synthesized in the anterior pituitary gland and from there secreted into the blood.
Hormones of the anterior pituitary gland
The pituitary gland is divided into two lobes: anterior and posterior. In the anterior hormones are directly synthesized and secreted into the blood. In the posterior pituitary, they come from the hypothalamus and are secreted into the blood only under certain circumstances.
Gonadotropic pituitary hormones stimulate the functioning of the gonads. These include:
- FSH is a follicle-stimulating hormone. It promotes ovogenesis and spermatogenesis. It is a complex protein (glycoprotein), which includes amino acids combined with carbohydrates.
- LH is a luteinizing hormone. Promotes the release of the egg from the ovary, affects the secretion of sex hormones (estrogen, progesterone), in men it causes the secretion of androgens. The amount of the hormone changes during one menstrual cycle, proportional and synchronous secretion of a certain amount of FSH and LH occurs.
The production of hormones is carried out in the gonadotropes (basophilic cells) of the adenohypophysis. They make up about 15% of all cells of the anterior lobe.
Pregnancy Hormone - HCG
When fertilization and implantation of the ovum into the uterine wall in the body of a woman, specific pituitary gonadotropic hormones, represented by chorionic gonadotropin, begin to be produced.
The hormone's functions include maintaining the corpus luteum (secretion of estrogen and progesterone) until the placenta fully ripens. It has a high luteinizing effect on the body, which is significantly superior to FSH and LH.
Structural features of hormones
The biological activity of hormones is ensured by their unique structure, which includes two subunits. The first, the α-subunit, has an almost identical structure in all gonadotropic hormones, while the β-subunit provides a unique effect of the hormone.
Individually, these subunits do not have any effect on the body, but when they combine, their biological activity and influence on the vital processes of the body, in particular, the reproductive system, are ensured. Thus, gonadotropic hormones have an important effect not only on the sexual sphere, but also on endocrine processes, and on the regulation of hormonal balance.
How hormones affect the body
Since ancient times, scientists have sought to study the biological activity of hormones and their effect on the human body. Gonadotropic hormones have a great influence on the vital processes of the human body. Therefore, the study of the mechanism of their action is a very important and interesting question. When conducting studies with labeled hormones, it was possible to establish that cells are able to recognize a specific hormone, and bind only to certain cells.
The process of binding to the cell is carried out by the presence of a protein molecule, the receptor, in the membrane or inside the cell itself. Intracellular reception refers to steroid hormones, since they tend to penetrate into the cell and affect its work. Membrane reception is characteristic of protein hormones that bind to the membrane membrane of the cell.
The binding of the hormone to the receptor protein promotes complex formation. This stage takes place without the participation of enzymes and is reversible. Steroid hormones penetrate the cell, bind to the receptor. After transformation, the formed complex penetrates the cell nucleus and promotes the formation of a specific RNA, in the cytoplasm of which there is a synthesis of enzymatic particles, which determine the effect of hormones on the cell.
Gonadotropic hormones: functions and effects on the processes of the reproductive system
FSH is most active in females. It stimulates the growth of follicular cells, which under the influence of HSCI turn into vesicles and mature before the stage of ovulation.
Under the influence of FSN, an increase in the mass of ovaries and testes is observed. However, even with the artificial introduction of synthetic hormone, it is impossible to cause the development of interstitial tissue, which affects the secretion of androgens of a testicular nature.
GSIC is responsible for ovulation and formation of the corpus luteum in the ovaries. Also, together with follicle-stimulating hormone, it affects the secretion of estrogen. Under the influence of a hormone that stimulates interstitial cells, the growth of organs responsible for secondary sexual characteristics occurs.
Biological effect of LTH
LTH is very similar to growth hormone. After laboratory studies, it was revealed that they are in the same molecule, therefore, each of these hormones cannot be isolated in a person. The functions of LTH include the secretion of milk and progesterone. It is important to note here that these processes are caused by the interaction of a large number of hormones, since when the body is exposed to only LTH, these functions do not appear.
So, for the allocation of milk, the following hormones are necessary:
- FSH and GSIK - cause the secretion of estrogen in the ovaries;
- under the influence of STH and estrogens, the growth of the milk ducts occurs;
- LTH causes progesterone secretion in the corpus luteum;
- progesterone stimulates the full development of the mammary gland at the alveolar-lobular level.
Gonadotropic hormones require regular interaction to ensure the full activity of the body and all its systems. That is why the separate influence of each of them (in the case of the introduction of synthetic hormones) does not cause the expected reaction of the body.
Hypothalamic hormone
The hypothalamus secretes gonadotropin releasing hormone into the blood. It has a polypeptide structure and affects the secretion of pituitary hormones. It has a greater effect on luteinizing hormone, and then on follicle-stimulating. GnRH is produced at clearly defined time intervals, in women they vary from 15 to 45 minutes (depending on the cycle), and in men, the hormone is secreted every 90 minutes.
With the artificial introduction of synthetic hormone through a dropper, hormone secretion functions are disrupted, which consists in a short-term increase in secretion, and then in the complete cessation of the production of gonadotropic hormones by the anterior pituitary gland.
The effect of gonadoliberin on the body
GnRH provides stimulation of the anterior pituitary lobe, the cells of which (gonadotropins) have a specific gonadoliberin receptor for the secretion of follicle-stimulating and luteinizing hormones, which, in turn, affect the functioning of the gonads.
FG stimulates the maturation of sperm and eggs, LH affects the secretion of sex hormones (estrogen, progesterone, testosterone). Under the influence of sex hormones, the cells of the reproductive system mature and become ready for fertilization.
When the processes of ovogenesis and spermatogenesis are excessively fast, inhibin is released, which affects the gonadotropic hormones of the anterior pituitary gland, which helps to slow down the maturation of germ cells by acting on follicle-stimulating hormone.
What are gonadotropic drugs used for?
Increasingly, in medical practice, treatment occurs through the introduction of artificial hormones. For some endocrine diseases or disorders of the human reproductive system, gonadotropin hormones are used. Their introduction to a certain extent affects the production of sex hormones and the processes taking place in the body.
In the event of a violation of the synthesis of gonadotropic hormones, certain endocrine disorders (miscarriages in the first trimester, sexual immaturity, sexual infantilism, Simmonds disease and Sheehan syndrome) may develop.
To neutralize the data of the pathology, a blood test is carried out and an analysis of its hormonal composition. Then, drugs are prescribed that are necessary to restore the correct balance of hormones and, accordingly, the regulation of vital processes in the body.