Maturation of the juvenile rat testis after surgical treatment of cryptorchidism.

Rats were made bilaterally cryptorchid at 17 days of age and bilateral orchidopexy performed at 34 days of age. The epididymal content of androgen binding protein (ABP), the weight and morphology of the testis, the cross-sectional area of seminiferous tubules and the testicular concentration of testosterone were then studied at 34, 42, 59 and 120 days of age. Cryptorchidism was followed rapidly by progressive inhibition of spermatogenesis and testicular growth as well as by decreased Sertoli cell secretion of ABP. Orchidopexy resulted in a gradual restoration of spermatogenesis, and all impaired parameters seemed to improve at the same, fairly slow rate. Restoration was not complete, but by 120 days of age the morphological appearance of the testis was compatible with recovery of normal fertility.