ALTERATIONS OF THE FINE-STRUCTURE AND ANDROGEN SECRETION OF THE INTERSTITIAL-CELLS IN THE EXPERIMENTALLY CRYPTORCHID RAT TESTIS

The ultrastructural features of the intertubular tissue of the adult rat testis have been studied following the induction of cryptorchidism by surgical translocation of the testes into the abdominal cavity. The principles of stereology were used to assess the changes in the cytological features of the Leydig cells that occur 4 weeks after inducing cryptorchidism. Following the induction of cryptorchidism the principal changes observed were the hypertrophy of the Leydig cells with respect to cellular size and the increased quantities of Leydig cell organelles, particularly the mitochondria, Golgi membranes and the smooth endoplasmic reticulum. Despite the increase in organelles associated with steroid biosynthesis, serum testosterone levels of cryptorchid animals were either significantly lower or remained unchanged from normal control values, although serum LH levels were consistently elevated following induction of cryptorchidism. Furthermore, stimulation of the cryptorchid testis with hCG resulted in a subnormal increase in serum testosterone levels. The cytological changes in the Leydig cells are suggestive of increased steroid secretion and the normal or lowered levels of testosterone in the peripheral circulation of cryptorchid rats indicate the possibility of a biosynthetic block of testosterone production or alternatively the conversion of testosterone to other metabolites by the seminiferous tubule compartment.