Endocrine function of the testis in streptozotocin diabetic rats.

The effects of experimental induced diabetes on the production, metabolism and transport of androgens in the rat testis were examined. Streptozotocin diabetes diminishes the serum and testicular levels of testosterone and increases the enzymic activity that converts testosterone to 5 alpha reduced metabolites, in the seminiferous tubules. The concentration of the androgen binding protein (ABP) in caput epididymis was also reduced in diabetic animals. Although the changes observed could be attributed to differences in gonadotropin production, these phenomena appear to be related to insulin deficiency, since the testes from diabetic rats treated for two weeks with insulin were capable to restore the parameters studied at levels comparable to that observed in normal animals. These data indicate that the testicular function may be regulated by the action of insulin.