Plasminogen activator secretion in the rat seminiferous epithelium after hypophysectomy and gonadotropin treatment

Secretion of plasminogen activators (PA) by seminiferous tubules of hypophysectomized and hypophysectomized gonadotropin-treated rats was studied. Adult male hypophysectomized rats were treated with daily subcutaneous injections of saline, FSH (5 i.u.), hCG (100 i.u.), or FSH + hCG. At six and 10 days posthypophysectomy, segments of seminiferous tubules at stages VII-VIII of the epithelial cycle were isolated for culture in a serum-free medium. PA activity was determined by an indirect solid-phase radiometric assay from conditioned media. PA secretion was significantly decreased in seminiferous tubules from rats treated with saline, FSH, or hCG, whereas normal PA secretion was found in seminiferous tubules of FSH + hCG-treated rats. It is concluded that both FSH and LH, via stimulation of androgen secretion, are needed for the maintenance of normal PA secretion by rat seminiferous tubules.