Recovery of testicular functions after surgical treatment of experimental cryptorchidism in the rat.

When rats were made unilaterally cryptorchid at 17 days of age (before spontaneous descensus), the further maturation of the testis was prevented. At 34 days of age, the abdominal testis was smaller than the scrotal testis and showed less secretion of the Sertoli cell specific androgen binding protein (ABP). In 120-130 days old rats that were made bilaterally cryptorchid at 17 days of age, testicular weight, histology, secretion of fluid and ABP were restored and testosterone secretion and fertility were normal if orchidopexy was performed at 33 days of age. If the orchidopexy was delayed until 59 days of age, the recovery of testicular function and morphology was only partial. The results show that in the rat, the testicular damage caused by cryptorchidism is reversible, if the abdominal testis is surgically descended during early sexual maturation.