[Functional interactions between somatic cells in the male gonad]

The existence of multiple interactions between somatic cells in the testis, has been suspected in vivo, and demonstrated in vitro by cocultures and cultures in the presence of conditioned media. Long term Sertoli-Leydig cell interactions results in a local regulation of the specific differentiated functions of these cells, and more precisely in a control of their responsiveness to their respective gonadotropin. Among the paracrine and/or autocrine factors, growth factors are involved in the control of differentiated functions. It is the case for IGF-I and TGF-beta, which respectively exhibit a stimulatory and inhibitory effect on Leydig cell functions and more specifically on LH responsiveness.