[Androgen--biosynthesis, receptor and action].

Androgens play a key role in promoting normal sex differentiation and development, pubertal masculinization, initiation of spermatogenesis, and maintenance of male sexual function. In addition to these classical function, androgens are significantly associated with cell differentiation, proliferation as well as carcinogenesis. The function of androgens can be mediated by the androgen receptor (AR), which transduces the steroid signal within cells. AR belongs to the superfamily of nuclear receptors that employ complex genetic mechanisms to control the development and physiological functions of target tissues. AR activates or represses gene transcription through association with specific DNA elements and/or proteins. Moreover, molecular investigations of AR gene structure have provided new insights towards defining a genetic basis for the relationship between the diseased conditions and androgen action. Recent data on androgen biosynthesis, action of androgens and molecular genetic analysis of gene structure have led to a new understanding of the pathology in affected men. This review summarizes briefly our current view of androgen action with a special emphasis on the alterations of AR.