Effect of Neonatal Androgens on Genitofemoral Spinal Motonucleus

Han, Sang Wen; Choi, Seung Kang

Abstract

The gubernaculum testis, which has an important role to play in transinguinal testicular descent is richly supplied by the genitofemoral nerve through its scrotal attachment. The treatment of pregnant rats with antiandrogen disturbed normal testicular descent in their male offspring. The division of the genitofemoral nerve in neonatal rats also disturbed normal descent of testis. The spinal motonucleus of genitofemoral nerve showed sexual difference. Therefore the genitofemoral motonucleus might be altered morphologically by manipulation of neonatal androgen as the other motonuclei showing sexual difference. This experiment was designed to illustrate the morphological relationship between the androgens and the genitofemoral motonucleus by retrograde tracing method in rats. Preliminarily the genitofemoral motonucleus of normal male and female adults were compared. The effects of neonatal androgen on genitofemoral rnotonucleus were evaluated by observing the motonuclei of adults after bilateral orchiectomy in neonates and androgen compensation. The results are summarized as follows. 1. The genitofemoral motonuclei of males were similar to those of females in location, but the number and the size of their cells were larger than those of females. 2. The bilateral orchiectomy in neonates caused atrophy of the cremasteric muscle and decreased the size and the number of genitofemoral motonucleus cells in adults. 3. The neonatal compensation of the androgen after bilateral orchiectomy could not prevent atrophy of the cremaster muscle, but maintained the number and the size of the genitofemoral motonucleus cells in adult compared to control. 4. The compensatory effects of androgens on the cellular size of genitofemoral motonucleus were obvious in dihydrotestosterone rather than testosterone. From the above results, it is concluded that the genitofemoral motonucleus show sexual difference and is morphologically affected by neonatal androgens. Therefore there could be the process that androgens, especially dihydrotestosterone, affects genitofemoral motonucleus which affects testicular descent in rats.