Androgens and the Aging Male

In contrast to women, men do not experience a sudden cessation of gonadal function comparable to menopause. However, there is a progressive reduction in male hypothalamic-pituitary-gonadal (HPG) axis function: testosterone levels decline through both central (pituitary) and peripheral (testicular) mechanisms, and there is a loss of the circadian rhythm of testosterone secretion. The progressive decline in testosterone levels has been demonstrated in both cross-sectional and longitudinal studies, and overall at least 25% of men over age 70 meet laboratory criteria for hypogonadism (ie, testosterone deficiency). Such age-associated HPG hypofunctioning, which has been termed "andropause," is thought to be…