Expression of androgen receptor protein within the lumbar spinal cord during ontologic development and following antiandrogen induced cryptorchidism.

One of the leading hypotheses regarding androgenic regulation of testicular descent is that the lumbar genitofemoral nucleus is morphologically altered by testosterone during a specific prenatal period. This hypothesis is based on the unproved assumption that androgen receptor is present in the fetal spinal cord. Using immunohistochemistry we identified androgen receptor in the rat lumbar spinal cord on gestational day 15, a day before the onset of maximal androgenic action for testicular descent. Experiments were performed to determine whether alterations in the morphology of the genitofemoral nucleus are associated with flutamide induced cryptorchidism. Studies revealed a reduction of motoneuron number in rats with flutamide induced cryptorchidism (124.2 +/- 18.9) compared to rats exposed to flutamide without cryptorchidism (269.3 +/- 20.2) and/or male controls (291.0 +/- 14.5, p < 0.01). These findings support the hypothesis that androgens can directly regulate development and morphology of the genitofemoral nucleus.