title: Genetics and hormones in testicular descent.
abstract: Testicular descent is an essential part of normal male sexual development. Any anomaly that disrupts normal testicular descent will be clinically evident as cryptorchidism. Several factors, such as Hoxa-10, epidermal growth factor (EGF), calcitonin gene-related peptide (CGRP), and hormones, especially androgens and insulin-like factor 3 (INSL-3), have been suggested as being regulators of testicular descent. Testicular descent from the lower pole of the kidney into the extra-abdominal scrotal sac is a two-stage process of transabdominal and inguino-scrotal migration. The transabdominal phase is androgen independent, whereas the inguino-scrotal phase depends on androgen action. Disruption of androgen action eg. by environmental anti-androgens are suspected as contributing to cryptorchidism. Estrogens can down-regulate INSL-3 production and thereby disturb testicular descent. Familial occurrence in some cases suggests a possible genetic background for cryptorchidism.
authors.affiliation: Departments of Physiology, University of Turku, FIN-20520 Turku, Finland.
authors.forename: Marko
authors.initials: M
authors.lastname: Kaleva
authors.forename: Jorma
authors.initials: J
authors.lastname: Toppari