Practice question

Male external genitalia differentiation depends predominantly on dihydrotestosterone acting via androgen receptor in genital tubercle and swellings. While testosterone maintains Wolffian duct derivatives, DHT binding induces conformational change stabilizing androgen receptor dimer that translocates to nucleus and binds androgen response elements regulating morphogenetic genes. DHT drives elongation of tubercle forming penis, canalization of urethra by fusion of urogenital folds, and formation of scrotum from labioscrotal swellings. Loss-of-function of 5α-reductase or receptor results in feminized external genitalia despite male internal anatomy, proving DHT critical.