Estrogen represents group of steroid hormones which are emitted with ovaries at women. A small amount of this substance, as well as the bark of adrenal glands made estrogen at both floors are also capable to synthesize man's testicles.

The main function of estrogen is a feminization of an organism, that is its reduction to a female look both outside, and from within. These hormones make the stimulating impact on development of a vagina, uterine tubes and a uterus.

Physiological concentration of this hormone strengthens release of vulval greasing, a differentiation and growth of a cellular epithelium of a vagina, channels and stromas of nipples, pigmentation in the field of generative organs and nipples, development of secondary sexual characteristics in the woman, growth of an epiphysis of tubular bones, promotes timely approach of periods, have procoagulant and anti-atherosclerotic action, increase the level of iron, copper and thyroxine in blood.

Sufficient level of estrogen increases the level of lipoproteins of high density, that is "good cholesterol" which protects vessels from atherosclerosis, reduces the level of "bad cholesterol". Also it is possible to distinguish increase in sensitivity of receptors of such steroid hormones from functions of this hormone as progestins and regulation of work of smooth muscles. Together with progesterone, estrogen promotes pregnancy approach, prepares an organism for the child's birth, increases a libido, influences a metabolism.

After a menopause the woman's organism practically ceases to produce estrogen. Decrease in their level usually is followed by temperature-controlled and vasomotor instability. The first of them is shown in so-called "inflow" of blood – that is sharp feelings of heat which can occur both occasionally, and is constant. Reduction of concentration of estrogen because of a menopause or a disease of ovaries also leads to sleep disorders, an atrophy of a reproductive system of the woman. One of the most dangerous effects of such deficit of hormone is shown in significant increase in risk of development of osteoporosis – to damages of a bone tissue as a result of which bones can be subject to changes because of thinning.

The increased concentration of estrogen brings to early sexual maturing, to forming of sexual characters on female type at both floors, the lowered concentration is a cycle cause of infringement at women.

Estrogen is widely applied as replacement hormonal therapy in time and after a menopause. According to many specialists therapy with use of this class of hormones allows the woman will get rid of a set of negative effects of aging of a reproductive system and an organism in general. Such impact of replacement therapy is connected with what for the woman is selected optimum, close to natural, the level of hormones. As a result of reception of such drugs quality of life of the woman can considerably will improve, up to disappearance of all negative effects of a menopause. However such replacement therapy with use of estrogen has also opponents who connect its use with development of malignant new growths in women.

Section: E