ANDROGENS are predominantly male steroid sex hormones that act directly to stimulate the development of male sex organs, and male secondary sexual characteristics, by acting at receptors on target tissues. Production is under the control of the pituitary hormone, corticotrophin. In men, androgenic steroids are produced primarily by the testes, and the main form is testosterone. However, in both men and women, androgens are also produced by the adrenal glands, and in women small quantities are also secreted by the ovaries. An excessive amount in women causes masculin-ization. There are also a number of synthetic androgens as well as natural hormones, used in medicine. They can be administered to make up hormonal deficiency (e.g. delayed puberty); for HRT (hormone replacement therapy) in menopausal women, and may also be used as anticancer treatment for sex-hormone-linked cancers (e.g. breast cancer in women). See ANTICANCER AGENTS.

Feminizing actions, particularly gynaecomastia, can occur in men receiving high doses of anabolic androgens. Androgens also have anabolic actions which promote tissue growth by increasing metabolic processes involving protein synthesis. Most anabolics are androgens with modified structure to enhance anabolic effects and minimize others. See ANABOLIC AGENTS.

Androgen antagonists are drugs that directly inhibit the actions of androgens, or indirectly inhibit production of androgens, and are also used in medicine. See ANTIANDROGENS; AROMATASE INHIBITORS.