Factors that mediate and modulate androgen action.

Androgens mediate a wide range of processes during embryogenesis and in the adult. In mammals, although a number of steroids can be shown to exert androgenic effects using in vitro and in vivo assays, testosterone and its 5alpha reduced metabolite, 5alpha-dihydrotestosterone (DHT) are considered to represent the principal physiologic androgens. Furthermore, although the effects that androgens exert differ widely among different tissues and cell types, genetic and biochemical data suggest that these effects are mediated via the protein products of a single androgen receptor gene, which is encoded on the X-chromosome in mammals.