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Androgen (from ''andro'' Greek prefix meaning masculine), also called androgenic hormone or testoid, is any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes the activity of the primary male sex organs and development of male secondary sex characteristics. Androgens were first discovered in 1936. Androgens are also the original anabolic steroids and the precursor of all estrogens. The primary and most well-known androgen is testosterone. Dihydrotestosterone (DHT) and androstenedione are less known generally, but are of equal importance in male development.〔 DHT in the embryo life causes differentiation of penis, scrotum and prostate. Later in life DHT contributes to male balding, prostate growth and sebaceous gland activity. ==Types== The main subset of androgens, known as adrenal androgens, is composed of 19-carbon steroids synthesized in the zona reticularis, the innermost layer of the adrenal cortex. Adrenal androgens function as weak steroids (though some are precursors), and the subset includes dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEA-S), and androstenedione. Besides testosterone, other androgens include: * Dehydroepiandrosterone (DHEA) is a steroid hormone produced in the adrenal cortex from cholesterol.〔(【引用サイトリンク】 Androgens )〕 It is the primary precursor of natural estrogens. DHEA is also called dehydroisoandrosterone or dehydroandrosterone. * Androstenedione (Andro) is an androgenic steroid produced by the testes, adrenal cortex, and ovaries. While androstenediones are converted metabolically to testosterone and other androgens, they are also the parent structure of estrone. Use of androstenedione as an athletic or bodybuilding supplement has been banned by the International Olympic Committee, as well as other sporting organizations. * Androstenediol is the steroid metabolite thought to act as the main regulator of gonadotropin secretion. * Androsterone is a chemical byproduct created during the breakdown of androgens, or derived from progesterone, that also exerts minor masculinising effects, but with one-seventh the intensity of testosterone. It is found in approximately equal amounts in the plasma and urine of both males and females. * Dihydrotestosterone (DHT) is a metabolite of testosterone, and a more potent androgen than testosterone in that it binds more strongly to androgen receptors. It is produced in the skin and reproductive tissue. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「androgen」の詳細全文を読む スポンサード リンク
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