[Status of the hypophyseal-gonadal system in male rats with diabetes (experimental study)]

The hypophyseo-gonadal system of male rats with streptozotocin-induced diabetes was studied. The hypophyseal sensitivity to LH releasing hormone was analyzed in vitro and concentrations of sex hormone nuclear receptors in the adenohypophysis, participating in gonadotropin secretion regulation according to a negative feedback mechanism, measured. Streptozotocin injection reduced blood testosterone concentration and levels of androgen nuclear receptors in the rat hypophysis. Blood LH and FSH levels in the rats with diabetes were virtually the same as in intact animals. In vitro experiments have demonstrated that diabetes development in rats did not influence the level of LH basal secretion by the hypophysis. The maximal response to LH releasing hormone was recorded in the control males in 3 h incubation, whereas the rate of LH secretion in the experimental animals did not differ from the normal one. The authors suggest that changed mechanism of the hypothalamo-hypophyseo-gonadal system regulation in experimental diabetes is related to the hypophyseal disorders, involving reduction of the LH-RH-stimulated gonadotropin release and of the testosterone receptor levels, this resulting in poor reproductive function control according to the negative feedback principle.