Local regulation of leydig cell function by inhibitors of steroidogenic activity

In the testis, local regulation of Leydig cell activity by paracrine factors can modify the response to LH. The identity of factors within paracrine actions has required the use of in vitro Leydig cell bioassay procedures, yet it has only recently been demonstrated that steroidogenic activity can be maintained in culture. There is renewed interest in the detection of both steroidogenic stimulatory and inhibitory activities using these systems, but this review presents the case for a role of inhibitory factors in the local regulation of Leydig cell function.