Sex hormones

Female sex hormones

Oestrogens are the hormones concerned with the maturation of the female genital tract, the development of the secondary sexual characteristics and bone formation. The main oestrogens, oestradiol and oestrone, are secreted by the theca interna and appear in the fluid of the Graafian Follicles. Oestrogens are also secreted by the placenta and to a much lesser degree by the adrenal cortex. They are rapidly metabolized in the liver.

Progesterone is the hormone concerned with the maintenance of pregnancy. It is secreted by the corpus luteum and acts only on tissues formerly sensitized by oestrogens. It inhibits ovulation during pregnancy, depresses the action of oestrogens and produces further development of the breasts. It also plays a role in the development of the placenta and depresses uterine contractility.

The production of steroid hormones is controlled by the pituitary gonadotrophins (follicle-stimulating and luteinizing hormones). In large doses oestrogens can depress the gonadotrophic and lactogenic activities of the anterior pituitary gland. Because of their rapid metabolism by the liver, oral administration of the natural oestrogens is less effective than parenteral administration, with the possible exception of oestriol, which is claimed to be as potent when given orally as when given by injection.

The oestrogens are used to treat menopausal disturbances and cases of dysmenorrhoea and menorrhagia. Progesterone is used chiefly in the treatment of functional uterine haemorrhagia.