Adult rat Sertoli cells secrete a factor or factors which modulate Leydig cell function

Abstract

ABSTRACT Production of testosterone and oestradiol-17β by Leydig cells from adult rats was stimulated by LH or dibutyryl cyclic AMP (10 and 2·5-fold respectively). The addition of spent medium from normal, hemicastrated or γ-irradiated rat seminiferous tubule cultures, as well as from Sertoli cell cultures, to purified Leydig cells further enhanced both basal (44 and 53% for testosterone and oestradiol-17β respectively) and LH-stimulated (56 and 18%) steroid output. Simultaneously, a decrease (20–30%) in intracellular cyclic AMP levels was observed. This stimulating factor (or factors) secreted by the Sertoli cells is different from LHRH, is of proteinic nature and has a molecular weight ranging between 10 000 and 50 000; its synthesis is not controlled by FSH nor by testosterone. This factor(s) involved in rat Leydig cell steroidogenesis, at a step beyond the adenylate cyclase, does not require protein synthesis for testosterone formation whereas it does for oestradiol-17β production. It should be noted that a germ cell–Sertoli cell interaction modulates the synthesis of this factor(s). J. Endocr. (1987) 114, 459–467