Effects of the induction of experimental cryptorchidism and subsequent orchidopexy on testicular function in immature rats.

Cryptorchidism surgically induced in 14-day-old rats, was allowed to persist until 35 days when one group was killed to assess testicular function. In a second group the cryptorchid testis was returned to the scrotum surgically (orchidopexy) and subsequently killed at 130 days. A third group remained persistently cryptorchid to 130 days, while in a fourth group two sham operations were performed at 14 and 35 days. At 35 days, cryptorchidism resulted in a significant decline in testis weight due to suppressed spermatogenesis. Sertoli cell function as measured by seminiferous tubule fluid (TF) production after unilateral efferent duct ligation and androgen-binding protein (ABP) production was significantly depressed in the cryptorchid group. Serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were significantly elevated with cryptorchidism but serum testosterone levels were unchanged. Although morphometric measurements showed no change in Leydig cells cross-sectioned area, in vitro human chorionic gonadotropin (hCG)-stimulated testosterone production was significantly increased in the cryptorchid group at higher hCG doses. Similar changes were found in cryptorchid testes at 130 days except that Leydig cell cross-sectional area was now significantly increased. Orchidopexy at 35 days restored spermatogenesis and fertility during test mating was not impaired. TF production, ABP accumulation and serum FSH levels returned to normal following orchidopexy.(ABSTRACT TRUNCATED AT 250 WORDS)

An assessment of Leydig cell function after bilateral or unilateral efferent duct ligation: further evidence for local control of Leydig cell function.

Leydig cell function was examined in adult male rats at 2 and 4 weeks after bilateral or unilateral efferent duct ligation. Bilateral efferent duct ligation resulted in significantly elevated serum LH levels, an increased size of Leydig cells and an enhanced testosterone response to gonadotropin stimulation in vitro despite a marked loss of LH-hCG receptors. After unilateral ligation of the vasa efferentia, the parameters of Leydig cell function in the ligated testes showed identical changes to those seen after bilateral ligation, whereas such changes were minor or absent in the unligated contralateral testes of the same animals. These results demonstrate that the modifications of Leydig cell function after efferent duct ligation are mainly due to local changes within the testes providing further evidence for an intratesticular control of Leydig cell function.