Development of Sertoli cell junctions in vitro--a freeze-fracture study

Structural response of adult rat Sertoli cells to peritubular fibroblasts in vitro

Sertoli cells were harvested from sexually mature rats and maintained in vitro for up to ten days (Sertoli cell-enriched cultures) or co-cultured with rat peritubular fibroblasts. Cultures were examined by differential light microscopy and by scanning or transmission electron microscopy. The presence of peritubular fibroblasts in co-culture greatly enhanced plating efficiency and viability of adult Sertoli cells. Sertoli cell aggregates preferentially adhered to peritubular cells, and by ten days had flattened and spread across these cells. Sertoli cells retained their characteristic ultrastructural features. Early in co-culture a collagen-like extracellular material was seen bridging Sertoli and peritubular cells, and its appearance was coincident with the presence of swollen rough endoplasmic reticulum in peritubular cells. Interperitubular cell spaces became engorged with a fibrillar material morphologically similar to the basal lamina of the seminiferous tubule wall. In the absence of peritubular cells, in culture medium "conditioned" by prior incubation with peritubular cells but not containing them, or when cultured with other fibroblastic cells, plating efficiency was low; Sertoli cells never flattened and cell ultrastructure progressively degenerated. The results indicated that peritubular cells support adult Sertoli cells in culture, possibly via extracellular material derived from peritubular cells, and suggest that Sertoli cells have an inductive effect on peritubular cell secretory activity.

Blood-testis barrier in men with idiopathic hypogonadotropic eunuchoidism and postpuberal pituiary failure

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 postpubertal 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.