Testicular atrophy associated with agenesis of the epididymis in the ACI rat.

The male ACI rat has a congenital Wolffian duct defect manifested by unilateral agenesis of the kidney, ureter, seminal vesicle, ductus deferens, and most of the epididymis. In the adult the testis on the affected side is markedly smaller than the contralateral testis and spermatogenesis is absent. In addition, in vitro perfusion of the affected testis revealed significantly less testosterone secretion than did the contralateral testis. Moreover, electron microscopy revealed that the smooth endoplasmic reticulum of the Leydig cell was significantly decreased. Thus, the affected testes clearly showed deranged spermatogenesis and Leydig cell structure and function. The ACI rat model may provide insight into the potential effects of congenital epididymal abnormalities on the testis of the human.