Hormones are diversified 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 secreted from there into the blood.
Anterior pituitary hormones
The pituitary gland is divided into two lobes: anterior and posterior. In the anterior, hormones are directly synthesized and released into the blood. In the posterior pituitary gland, they come from the hypothalamus and are secreted into the blood only under certain circumstances.
Gonadotropic hormones of the pituitary gland stimulate the work of the gonads. These include:
- FSH is a follicle-stimulating hormone. It promotes oogenesis and spermatogenesis. It is a complex protein (glycoprotein), which includes amino acids combined with carbohydrates.
- LH - luteinizing hormone. Promotes the release of the egg from the ovary, affects the secretion of sex hormones (estrogen, progesterone), causes the secretion of androgens in men. The amount of the hormone changesduring one menstrual cycle, there is a proportional and synchronous secretion of a certain amount of FSH and LH.
The production of hormones is carried out in the gonadotropes (basophilic cells) of the adenohypophysis. They make up about 15% of all anterior lobe cells.
Pregnancy Hormone - HCG
When fertilization and implantation of the fetal egg into the wall of the uterus in the body of a woman, specific pituitary gonadotropic hormones, represented by chorionic gonadotropin, begin to be produced.
The function of the hormone is to maintain the work of the corpus luteum (estrogen and progesterone release) until the placenta fully matures. It has a high luteinizing effect on the body, which is largely superior to FSH and LH.
Structural features of hormones
The biological activity of hormones is provided by their unique structure, which includes two subunits. The first, a-subunit, has an almost identical structure for all gonadotropic hormones, while the b-subunit provides the unique effect of the hormone.
Individually, these subunits do not have any effect on the body, but when they are combined, their biological activity and influence on the vital processes of the body, in particular, the reproductive system, is ensured. Thus, gonadotropic hormones have an important effect not only on the genital area,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 effects on the human body. Gonadotropic hormones have a great influence on the vital processes of the human body. Therefore, studying the mechanism of their action is a very important and interesting question. When conducting studies with labeled hormones, it was found that cells are able to recognize a certain hormone, and bind only to certain cells.
The process of binding to the cell is carried out by means of the presence in the membrane or inside the cell itself of a protein molecule - the receptor. Intracellular reception refers to steroid hormones, since they tend to penetrate 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 the formation of the complex. This stage takes place without the participation of enzymes and is reversible. Steroid hormones enter the cell and bind to the receptor. After transformation, the formed complex penetrates into the cell nucleus and promotes the formation of specific RNA, in the cytoplasm of which the synthesis of enzymatic particles occurs, which determines the action of hormones on the cell.
Gonadotropic hormones: functions and influence 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 GSIK, turn into vesicles and mature to the stage of ovulation.
Under the influence of FSN, an increase in the mass of the ovaries and testes is observed. However, even with the artificial introduction of a synthetic hormone, it is impossible to cause the development of interstitial tissue, which affects the secretion of androgens of a testicular nature.
HSIC is responsible for ovulation and the formation of a corpus luteum in the ovaries. Also, together with the follicle-stimulating hormone, it affects the secretion of estrogens. Under the influence of a hormone that stimulates interstitial cells, the organs responsible for secondary sexual characteristics grow.
Biological action of LTH
LTH is very similar to growth hormone. After laboratory studies, it was found that they are in the same molecule, so each of these hormones cannot be isolated separately from 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 only LTH is exposed to the body, these functions do not appear.
Thus, the following hormones are needed to produce milk:
- FSH and GSIK - cause estrogen secretion in the ovaries;
- under the influence of growth hormone and estrogens, the growth of the milk ducts occurs;
- LTH causes the secretion of progesterone in the corpus luteum;
- progesterone stimulates the full development of the mammary gland at the alveolar-lobular level.
Gonadotropic hormones requireregular interaction to ensure the full functioning of the body and all its systems. That is why the individual influence of each of them (in the case of the introduction of synthetic hormones) does not cause the expected reaction of the body.
Hypothalamus hormone
The hypothalamus secretes gonadotropic releasing hormone into the blood. It has a polypeptide structure and affects the secretion of pituitary hormones. To a greater extent, it has an effect on luteinizing hormone, and then on follicle-stimulating hormone. GnRH is produced at well-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 a synthetic hormone through a dropper, the functions of hormone secretion are disrupted, which consist 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 process of the effect of GnRH on the body
GnRH provides stimulation of the anterior pituitary lobe, whose cells (gonadotropins) have a specific GnRH 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, cells of the reproductive systemmature and become ready for fertilization.
When the processes of oogenesis 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 the follicle-stimulating hormone.
What are gonadotropins used for
Increasingly, in medical practice there is treatment through the introduction of artificial hormones. For some endocrine diseases or disorders of the human reproductive system, preparations of gonadotropic hormones are used. Their introduction to a certain extent affects the production of sex hormones and the processes occurring in the body.
In case of impaired synthesis of gonadotropic hormones, certain endocrine disorders may develop (miscarriages in the first trimester, sexual immaturity, sexual infantilism, Simmonds disease and Sheehan's syndrome).
To neutralize these pathologies, a blood test and an analysis of its hormonal composition are carried out. Then drugs are prescribed that are necessary to restore the correct balance of hormones and, accordingly, the regulation of vital processes in the body.
