[Origin and sites of action of inhibin (author's transl)]

Mice testis in organ culture (31 degrees C) produce a steroid free substance which inhibits FSH secretion by rat pituitary cells. Histologically, Sterloti cells alone remain normal after a few days in culture. A hypothalamic action of inhibin is demonstrated in vitro. The intraglandular content in LHRH is inversely related to the amount of inhibin present in the culture medium. In the testis, DNA synthesis is depended of inhibin. This is demonstrated by studies of the incorporation of tritiated thymidine in testicular DNA in vivo and in vitro. In conclusion, inhibin is produced by Sertoli cells and acts not only at this pituitary level but also on the hypothalamus and the testis.