▪ Abstract  My work in physiology was designed to investigate the process of androgen action within target cells and to use this information to provide insight into the clinical disorders of androgen action. The discovery that the circulating male androgen testosterone is 5α-reduced to a more potent hormone, dihydrotestosterone, in target tissues and that dihydrotestosterone and testosterone work by binding to the same androgen receptor protein has provided insight into the inherited syndromes of androgen resistance that impair the formation of the male urogenital tract during embryogenesis and into the role of continued dihydrotestosterone formation in the pathogenesis of prostatic hyperplasia in dogs and men.