Morphological changes in the hypothalamic-hypophyseal-gonadal axis of male rats after twelve months of streptozotocin-induced diabetes

The hypothalami, pituitaries and testes from streptozotocin-treated and control male Wistar rats were examined by light and electron microscopy 12 months after induction of diabetes. Light and electron microscopic immunohistochemical techniques were employed for the localization of luteinizing hormone-releasing hormone and luteinizing hormone in the hypothalami and the pituitaries. In the hypothalami of diabetic animals swollen neuronal processes containing anti-luteinizing hormone-releasing-hormone positive material were frequent. In the pituitaries of the same animals a large number of small luteinizing hormone-gonadotrophs was found. These cells contained numerous secretory granules and were deficient in endoplasmic reticulum. The average testicular weight of the diabetic rats was significantly reduced but with marked individual variations. Histologically, the testes with the highest weights appeared normal, those with the lowest weights atrophic with few degenerating Leydig cells. These hypothalamic-hypophyseal changes are probably responsible for the testicular lesions found in experimental diabetes mellitus and may have relevance to the problem of infertility in human diabetes.