Androgens: Basic biology and clinical implication

Although androgens have been considered essential modulators of bone biolog y in men, recent studies have indicated that estrogen may have an important , if not dominant, role. Nevertheless, there is strong evidence that androg ens have independent skeletal actions. Nonaromatizable androgens influence a variety of aspects of bone cell biology and are capable of modulating bon e remodeling and bone mass. It appears that androgens are particularly impo rtant in the control of periosteal bone formation, an effect that might und erlie the gender difference in bone size. Alterations in androgen receptor function affect bone metabolism, and new information suggests that androgen s modulate receptor homeostasis. The clinical implications of androgen effe cts, and how they interact with those of estrogens, are somewhat unclear. I t is likely that overall bone homeostasis and gender differences depend on a combination of androgenic and estrogenic actions. Androgens may well prov ide advantages in the prevention and therapy of metabolic bone disorders in both men and women.