FSH acts on the proliferation of type A spermatogonia via Nur77 that increases GDNF expression in the Sertoli cells.

The molecular mechanism responsible for the regulation of GDNF in Sertoli cells remains largely unknown. In the present study, FSH induced the expression of Nur77 and GDNF in mouse testis tissue and human fetal Sertoli cells. Moreover, FSH increased the number of A spermatogonia co-cultured with Sertoli cells. In the additional assays, Nur77 was observed to directly regulate GDNF transcription. Furthermore, overexpression of Nur77 and siRNA-mediated knockdown of Nur77 affected levels of GDNF mRNA and protein in primary human fetal Sertoli cells. These results indicate that FSH-induced Nur77 regulates the expression of GDNF in Sertoli cells to stimulate the proliferation of A spermatogonia in vitro.