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Progesterone represents one of hormones of ovaries, namely – a yellow body. On the chemical structure this hormone belongs to steroid group. Also progesterone is a predecessor of some neurosteroids which are developed by a brain.
Besides, this hormone in big to quantities is made by a placenta during pregnancy, with progressive increase from the first to the third trimester, and some days before childbirth its concentration of progesterone sharply falls.
At women the main function of hormone consists in creation of a possibility of approach of pregnancy, and also in its maintenance, that is a gestation. From there hormone also received the name. Also it promotes development of a normal secretory endometria in women, providing transition of a cover of a uterus to a secretory phase from a proliferation stage. After fertilization progesterone promotes transition of a uterus being able, suitable for communication with an oospore.
Progesterone provides decrease in an expression of receptors of estrogen in an endometria, proliferative activity of cells of this fabric, protects an organism from development of cystous and ferruterous regeneration of an endometria and a hyperplasia under the influence of estrogen. Just on an endometria also connect development of a hyperplasia at such states as a hyper oestrogenic phase of a climax, a syndrome of polycystic ovaries with absence or insufficiency of influence of progesterone, etc.
This hormone is also necessary for normal development of a mammary gland. It stimulates growth of trailer elements of gland, a differentiation of channels and segments, promotes final maturing of a breast at girls. Along with it, progesterone can lower an expression of oestrogenic receptors in a mammary gland, protect from a mastopathy, a hyperplasia, fibrocystic defeats at influence of estrogen, etc. Some specialists assume that prevention of repeated pregnancies in the presence of a breast cancer is connected with such function of hormone.
Progesterone is capable to lower contractility and excitability of muscles of uterine tubes and a uterus several mechanisms. Hormone activates specific enzymes which split vasopressin and oxytocin. Also it lowers sensitivity of a uterus to these hormones, lowers the level of prostaglandins in myometriums, increasing activity of enzymes which are responsible for their disintegration.
Possibly, ability of this hormone to reduce pain during periods also is connected with ability of progesterone to lower the level of prostaglandins in an endometria and myometriums. Its insufficiency is often connected with manifestations of a premenstrual syndrome.
Also progesterone has anti-androgenic effect thanks to reduction of formation of a metabolite of a testesteron and due to increase in level of globulin which connects sexual steroids.
Drugs with the content of this hormone are actively used in medical practice. Generally natural progesterone is used according to indications which are connected with insufficient development by an organism of this hormone, and all following effects. At the moment in Russia various medicines of natural progesterone allowing to enter hormone vaginalno, outwardly, in the form of intramuscular injections, and also inside are registered. Also there is a number of the means using synthetic analog in the basis. Cumulative effect of progesterone consists in its ability to cause transition of a cover of a uterus from one phase in another. However synthetic analogs do not possess a full range of qualities of endogenous progesterone.