Influence of streptozotocin-induced diabetes and insulin treatment on the pituitary-testicular axis during sexual maturation in rats.

Effects of streptozoticin (STZ) - diabetes and insulin treatment on the functioning of pituilary-testicular axis during sexual maturation was studied. Prepubertal (30 days old) and pubertal (50 days old) male Wistar rats were made diabetic by a single injection of STZ. A group of diabetic rats was given insulin (3U/ 100 g b. wt./day in 2 equally divided doses). 3 days after STZ treatment. Prepubertal and pubertal rats of all groups were killed on postnatal days 51 and 71, respectively. STZ-diabetes caused marked reduction in serum LH. FSH, prolactin, testosterone and testicular interstitial fluid testosterone as well as the activities of Leydig cellular steroidogenic enzymes (3β-an(17β-hydroxysteroid dehydrogenases). Insulin treatment to diabetic rats maintained these changes at control range except FSH and prolactin in prepubertal rats. The results indicate that (i) diabetes-induced steroidogenic lesions in Leydig cells represent a direct consequence of dysfunctioning of pituitary-testicular axis. (ii) the adverse effects of diabetes on pituitary-testicular functions are influenced by age of its induction and (iii) optimum insulin level is essential for the acquisition of Leydig cellular steroidogenic efficacy during sexual development.