Gonadotropin binding sites in human postmenopausal ovaries

Glucose-6-phosphate dehydrogenase (G6PD) activity and gonadotropin binding sites were localized within seven postmenopausal ovaries. G6PD was localized in the cells of cortical stroma and hilus using a histochemical technique for the reduction of the tetrazolium salt, Nitro-Blue tetrazolium. Gonadotropin binding sites were localized by autoradiography following incubation of ovarian sections with (125I-hLH) and 125I-labeled follicle-stimulating hormone (125I-hFSH) were identified in the cortical stroma and hilus cells. Since these cells contain G6PD and other enzymes necessary for steroidogenesis and also have the capacity to bind both hLH and hFSH, steroidogenesis in postmenopausal ovaries appears to be controlled by circulating gonadotropins. Blood vessels within postmenopausal ovaries also bound both gonadotropins, but 125I-hFSH binding was often more intense than 125I-hLH binding.