Andropause

Abstract

In men, aging is associated with progressive impairment of testicular function. Decrease in total testosterone levels with aging has been reported in many studies in normal healthy men. This decrease has a primarily testicular origin, as shown by decreased number of Leydig cells in histological studies, increased basal gonadotropin levels and decreased response to hCG. A greater decrease in bioavailable testosterone rather in than total testosterone concentrations is explained by the age-dependent increase in the SHBG concentration. Although immunoreactive gonadotropin levels are higher than in young men, a relative alteration of bioactive gonadotropin secretion by the pituitary occurs in elderly men. Although the definitive demonstration of an alteration of GnRH secretion by the hypothalamus cannot be established in healthy elderly men, such an alteration might be responsible for a decompensation of the testicular function in case of inter-current illness. Increased FSH and decreased inhibin plasma levels are indicating a similar alteration in seminiferous tubules as directly demonstrated by histological data showing a decrease of Sertoli cell number and daily sperm production with aging. Although the incidence of sexual dysfunction increases with aging, the relationship between sexual behaviour and testicular endocrine function remained a mater of controversy. A threshold of testosterone action on sexual behavior might be responsible for the difficulty in establishing this relationship. Although some controlled studies are available, the risk-to-benefit balance of androgen substitution in older male remained a controversial issue. A positive effect on sense of well-being and/or libido has been and the lack of adverse effect on lipid and carbohydrate metabolism had been demonstrated in short term studies, however, the role of androgens in the benign hypertrophy of the prostate and in stimulating the growth of latent prostate adenocarcinoma remained to be more clearly established by long-term controlled studies.