Further evidence for inhibin: change in serum luteinizing hormone and follicle-stimulating hormone levels after X-irradiation of rat testes

Department of Medicine, Mount Sinai Hospital and University of Toronto, Toronto, Ontario M5G 1X5, Canada (Received 2 December 1974) It has been postulated that testicular tubules are responsible for the production of a substance, inhibin, which selectively inhibits or modulates the secretion of follicle-stimulating hormone (FSH) by the pituitary gland. Testicular germinal cell depletion such as that seen after chemotherapy for lymphoma resulted in a rise of serum FSH while luteinizing hormone (LH) changed very little or not at all (Van Thiel, Sherins, Myers & De Vita, 1972). In 1968, Paulsen reported that X-irradiation of human testes resulted in germinal cell depletion with a concomitant rise in urinary FSH levels. These studies suggest that germinal cells produce an FSH regulating substance which is lost when germinal tissue is destroyed. Setchell & Jacks (1974) demonstrated that selective FSH suppression could be achieved in male or female rats injected with rete testis