Abstract
Immature-type Sertoli cells in the testes of idiopathic hypogonadotropic eunuchoidism (17-30 years of age) had no specialized junctions. The specialized Sertoli junctions that blocked the penetration of lanthanum were formed six months to two years after hCG treatment (5000 IU twice a week) in patients of hypogonadotropic eunuchoidism. In two patients with postpuberal pituitary failure (one had a ectopic pinealoma, irradiated one year ago, and the other had a pituitary adenoma, hypophysectomized four years ago), the ultrastructural integrity of these Sertoli junctions was maintained. Therefore, it may be suggested that the development of the blood-testis barrier is dependent on gonadotropins, but the maintenance of the blood-testis barrier is not.