Androgen Replacement Therapy of Male Hypogonadism

Abstract

Male hypogonadism is a relatively common disorder in clinical practice, particularly in aging men, and has significant effects on the fertility, sexual function, and general health of patients (1–8). Disorders of sperm and testosterone (T) production may be caused by primary, secondary, or tertiary hypogonadism. Some are relatively common and others are rare (9–11). In aging men, a tertiary-like deficiency leads to T deficiency, which affects about 20% of men by age 60 yr (5,12–14). In men with clinical manifestations of primary or secondary hypogonadism, deficiency of T can usually be treated effectively. Fertility in some men with primary testicular disease, such as Klinefelter’ s syndrome, is irreversible, but those with gonadotropin deficiency resulting in infertility can often be treated successfully (as reviewed in Chapter 24) (15–17). Although both T deficiency and infertility can be corrected using gonadotropin or gonadotropin-releasing hormone (GnRH) therapy in men with hypogonadotropic hypogonadism, this form of therapy is usually restricted to the management of infertility. Otherwise, androgen-replacement therapy is used to correct the chronic T deficiency. Thus, knowledge of the pathophysiology of hypogonadism is needed to plan and use appropriate hormonal replacement therapy in men with deficiency of T and sperm production.