Paracrine interactions between the interstitial and the tubular compartment of the testis.

In the present paper we will briefly review the role of testicular peptides in the interactions between the tubular and the interstitial compartment. Two interactions are discussed in some more detail. 1) It is shown that the effects of FSH on Leydig cell function may be mediated by at least three types of diffusible mediators produced by Sertoli cells: SCF (a 10-30 kD protein), IGF-I and one or more other still unidentified factors. 2) Evidence is presented that some of the effects of androgens on Sertoli cells may be mediated by diffusible factors produced by peritubular cells and that similar or identical mediators are also produced by prostatic stromal cells.