testosterone

testosterone The principal androgenic hormone produced by the testes. Testosterone is made by the testes in response to luteinizing hormone from the pituitary gland. Androgens promote the development of adult male sex characteristics, such as deep voice; they strengthen muscle and bone mass; and they stimulate spermatogenesis, the production of sperm. High levels of testosterone appear to promote good health in men, lowering the risk of high blood pressure and heart attack, for example. High testosterone levels may also correlate with risky behavior, however, including increased aggressiveness and smoking, which may cancel out these health benefits. See also androgen; testosterone replacement therapy.