Oestrogen Health Dictionary

A site on the membrane surrounding a cell (see CELLS) that binds to the hormone OESTROGENS. This activates the cell’s reaction to the hormone. Anti-oestrogen drugs such as TAMOXIFEN used to treat breast cancer (see BREASTS, DISEASES OF) prevent the oestrogen from binding to these receptors.... oestrogen receptor

Natural or synthetic substances that induce the changes in the UTERUS that precede OVULATION. They are also responsible for the development of the secondary sex characteristics in women: that is, the physical changes that take place in a girl at puberty, such as enlargement of the BREASTS, appearance of pubic and axillary hair, and the deposition of fat on the thighs and hips. They are used in the management of disturbances of the MENOPAUSE, and also in the treatment of cancer of the prostate (see PROSTATE GLAND, DISEASES OF) and certain cases of cancer of the breast.

The oestrogenic hormones of the ovary are OESTRADIOL and oestrone. The rapid degradation of natural oestrogens limits their use as therapeutic agents. Chemical substitution of the steroid molecule, as in ethinyl oestradiol, or the use of a non-steroidal synthetic oestrogen such as STILBOESTROL, greatly reduces the rate of degradation and enhances the therapeutic action. A further development has been the use of compounds which are not actually oestrogenic themselves, but which are slowly metabolised to oestrogenic substances, or substances such as chlorotrianisene, which are taken up in the body fat and then slowly released into the circulation. There is in fact little to choose between the various synthetic oestrogens. Ethinyl oestradiol is the most potent oral oestrogen, being 20 times more active than stilboestrol.

Other commonly used oestrogen drugs are dienoestrol and oestrol. The use of oestrogens in hormone replacement therapy (HRT) is dealt with in the entry on the MENOPAUSE.... oestrogens

See OESTROGENS.... equine oestrogens

A group of synthetically produced drugs that are used in oral contraceptives and to supplement or replace the body’s own oestrogen hormones.

Oestrogen drugs are often used together with progestogen drugs.

Oestrogens suppress the production of gonadotrophin hormones, which stimulate cell activity in the ovaries. High doses are used in postcoital contraception to prevent conception (see contraception, emergency). They are also used to treat, or sometimes prevent, menopausal symptoms and disorders. Oestrogens may be used to treat certain forms of infertility, female hypogonadism, abnormal menstrual bleeding, prostatic cancer (see prostate, cancer of), and certain types of breast cancer.

Oestrogens may cause breast tenderness and enlargement, bloating, weight gain, nausea, reduced sex drive, depression, migraine, and bleeding between periods. Side effects often subside after 2 or 3 months. The drugs can increase the risk of abnormal blood clotting and susceptibility to high blood pressure (see hypertension). Oestrogen drugs should not be taken in pregnancy as they may adversely affect the fetus.... oestrogen drugs

A group of hormones that are essential for normal female sexual development and healthy functioning of the reproductive system.

In women, they are produced mainly in the ovaries and also in the placenta in pregnancy.

Small amounts are produced in the adrenal glands in both men and women, but oestrogens have no known specific function in men.

When levels are low, oestrogen hormones can be replaced with oestrogen drugs.... oestrogen hormones

Oestrogens that occur naturally in plants.... phyto-oestrogens

(oestrogen-receptor antagonist) n. one of a group of drugs that oppose the action of oestrogen by binding to *oestrogen receptors in the body’s tissues. The most important of these drugs is currently *tamoxifen, which is used in the treatment of breast cancers dependent on oestrogen. Because they stimulate the production of pituitary *gonadotrophins, some anti-oestrogens (e.g. *clomifene, tamoxifen) are used to induce or stimulate ovulation in infertility treatment. Side-effects of anti-oestrogens include hot flushes, itching of the vulva, nausea, vomiting, fluid retention, and sometimes vaginal bleeding.... anti-oestrogen

see anti-oestrogen.... oestrogen-receptor antagonist