Testosterone is the most important of the androgens (male sex hormones). Testosterone stimulates bone and muscle growth and sexual development. It is produced by the interstitial cells of the testes (and in very small amounts by the ovaries) and to a lesser extent by the adrenal gland cortex, under the control of luteinizing hormone.
Drug therapy using testosterone
Synthetic or animal testosterone is used to stimulate puberty or to treat infertility in males suffering from deficiency caused by disorders of the testes or pituitary gland. Testosterone was formerly used in the treatment of breast cancer but is now rarely used for this purpose.
Excess testosterone given to stimulate puberty may interfere with normal growth or cause over-rapid sexual development. In males, testosterone may cause priapism (painful, persistent erection). In females, high doses of testosterone may cause deepening of the voice, excessive hair growth, or hair loss. Treatment with some orally-administered forms of testosterone may cause liver damage.