Hormonal regulation of testicular descent: experimental and clinical observations.

Hormonal regulation of testicular descent has been investigated. Based on experimental studies using the rat and on a review of clinical material it has been determined that testicular descent is an androgen-mediated event directly under the regulation of pituitary gonadotropin. Furthermore, the active androgenic metabolite involved in this process appears to be dihydrotestosterone, which is synthesized by the testis and must be present in high local concentrations to be effective. In addition to these hormonal requirements the anatomy of the inguinal canal must provide unimpeded migration of the testis into the scrotum. Any imbalance or anomaly of these prerequisites may lead to cryptorchidism.