Fine structure of the Sertoli cells of the rat testis in experimental unilateral cryptorchidism.

Mature rats were made unilaterally cryptorchid for 28 days. ABP concentrations of the abdominal epididymis were significantly reduced, indicating impaired secretory activity of the Sertoli cells. The FSH serum level was increased and testosterone levels both of the serum and of homogenates of the cryptorchid testis were slightly reduced. Sertoli cells of the cryptorchid testis showed signs of regression. Although Sertoli cell junctions were still impermeable to lanthanum, a reduction of membrane particles forming the Sertoli cell junctions was observed in freeze-fracture replicas. In thin sections it was seen that the plasma membrane-apposed cisternae of endoplasmic reticulum or the adjaacent microfilaments were partially lacking. No such changes were observed in the scrotal testis.