Androgen Health Dictionary

Androgen: From 2 Different Sources


The general term for any one of a group of HORMONES which govern the development of the sexual organs and the secondary sexual characteristics of the male. TESTOSTERONE, the androgenic hormone formed in the interstitial cells of the testis (see TESTICLE), controls the development and maintenance of the male sex organs and secondary sex characteristics. In small doses it increases the number of spermatozoa (see SPERMATOZOON) produced, but in large doses it inhibits the gonadotrophic activity of the anterior PITUITARY GLAND and suppresses the formation of the spermatozoa. It is both androgenic and anabolic in action. The anabolic e?ect includes the ability to stimulate protein synthesis and to diminish the catabolism of amino acids, and this is associated with retention of nitrogen, potassium, phosphorus and calcium. Doses in excess of 10 mg daily to the female may produce VIRILISM.

Unconjugated testosterone is rarely used clinically because its derivatives have a more powerful and prolonged e?ect, and because testosterone itself requires implantation into the subcutaneous fat using a trocar and cannula for maximum therapeutic bene?t. Testosterone propionate is prepared in an oily solution, as it is insoluble in water; it is e?ective for three days and is therefore administered intramuscularly twice weekly. Testosterone phenyl-propionate is a long-acting microcrystalline preparation which, when given by intramuscular or subcutaneous injection, is e?ective for four weeks. Testosterone enantate is another long-acting intramuscular preparation. Mesterolone is an e?ective oral androgen and is less hepatoxic: it does not inhibit pituitary gonadotrophic production and hence spermatogenesis is unimpaired. Testosterone undecanoate is also an e?ective oral form.

Health Source: Medical Dictionary
Author: Health Dictionary
n. one of a group of steroid hormones, including *testosterone and *dihydrotestosterone, that stimulate the development of male sex organs and male secondary sexual characteristics (e.g. beard growth, deepening of the voice, and muscle development). The principal source of these hormones is the testis (production being stimulated by *luteinizing hormone) but they are also secreted by the adrenal cortex (see dehydroepiandrosterone) and ovaries in small amounts. In women excessive production of androgens gives rise to *masculinization.

Naturally occurring and synthetic androgens are used in replacement therapy (to treat such conditions as delayed puberty in adolescent boys, *hypogonadism, and impotence due to testicular insufficiency) and as *anabolic agents. Side-effects include salt and water retention, increased bone growth, and masculinization in women. Androgens should not be used in patients with cancer of the prostate gland or in pregnant women. —androgenic adj.

Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Androgen Drugs

Natural or synthetic androgen hormones used as drugs; one of the most important is testosterone. These drugs are used in the treatment of male hypogonadism (underactivity of the testes) to stimulate the development of sexual characteristics.

Androgen drugs are occasionally used to treat certain types of breast cancer. They have been widely used by sportsmen wishing to increase muscle bulk and strength, a practice that is dangerous to health (see steroids, anabolic).

Adverse effects include fluid retention, weight gain, increased blood cholesterol, and, rarely, liver damage. When taken by women, the drugs can cause male characteristics, such as facial hair, to develop.

androgen hormones A group of hormones that stimulate the development of male sexual characteristics.

Androgens are produced by specialized cells in the testes in males and in the adrenal glands in both sexes. The ovaries secrete very small quantities of androgens until the menopause. The most active androgen is testosterone, which is produced in the testes. The production of androgens by the testes is controlled by certain pituitary hormones, called gonadotrophins. Adrenal androgens are controlled by ACTH, another pituitary hormone.

Androgens stimulate male secondary sexual characteristics at puberty, such as the growth of facial hair and deepening of the voice. They have an anabolic effect (they raise the rate of protein synthesis and lower the rate at which it is broken down). This increases muscle bulk and accelerates growth. At the end of puberty, androgens cause the long bones to stop growing. They stimulate sebum secretion, which, if excessive, causes acne. In early adult life, androgens promote male-pattern baldness.

Androgen deficiency may occur if the testes are diseased or if the pituitary gland fails to secrete gonadotrophins. Typical effects include decreased body and facial hair, a high-pitched voice, underdevelopment of the genitalia, and poor muscle development.

Overproduction of androgens may be the result of adrenal disorders (see adrenal tumours; adrenal hyperplasia, congenital), of testicular tumours (see testis, cancer of), or, rarely, of androgensecreting ovarian tumours (see ovary, cancer of).

In men, excess androgens accentuate male characteristics; in boys, they cause premature sexual development.

In women, excess androgens cause virilization, the development of masculine features such as an increase in body hair, deepening of the voice, clitoral enlargement, and amenorrhoea.... androgen drugs

Androgen Insensitivity Syndrome

(AIS) an X-linked (see sex-linked) disorder in which the body does not react to androgens because of structural abnormalities in androgen receptors. In its most extreme form, complete AIS (formerly known as testicular feminization syndrome), there is a fully female body appearance with breast development and a short vagina (but no uterus; testes are present internally). Psychosexuality is female orientated. Partial AIS is also known as *Reifenstein’s syndrome.... androgen insensitivity syndrome

Androgenization

n. the final effects of the exposure of sensitive tissues to androgens, i.e. the development of secondary male sexual characteristics. Androgenization can also occur abnormally in females, who may develop excessive body hair, male-pattern baldness, and *clitoromegaly.... androgenization

Anti-androgen

n. any one of a group of drugs that inhibit the action of testosterone on the prostate gland by blocking androgen receptors, competing for binding sites, or decreasing androgen production. They are therefore used in the treatment of prostate cancer, which is an androgen-dependent tumour. Anti-androgens include *abiraterone acetate, *bicalutamide, *cyproterone, *finasteride, and *flutamide.... anti-androgen



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