Effect of insulin on testicular alterations in the nonobese diabetic mouse.

Severe spermatogenic alterations occur in association with diabetic manifestations in the nonobese diabetic (NOD) mouse. A study was undertaken to determine whether or not administration of insulin during initial appearance of diabetic changes could inhibit the interference with spermatogenesis. Male NOD mice injected with cyclophosphamide to promote onset of overt diabetes were divided into insulin-treated and nontreated groups. Testicular specimens were then examined by light and electron microscopy. Insulin-treated animals showed variable changes ranging from normal spermatogenesis to moderate to severe alterations. Animals with diabetes that did not receive insulin exhibited extensive spermatogenic disruption. The findings indicate a blunting of testicular damage when insulin is administered early in the development of diabetic manifestations. Although spermatogenic abnormalities could not be prevented entirely by insulin treatment, the results provide evidence for a direct metabolic effect on the pathogenesis of the testicular alterations.