Summary:
Effects of streptozotocin (STZ) — diabetes and insulin treatment on the functioning
of pituitary-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-and 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.
Key words:
Streptozotocin-diabetes - insulin - Leydig cell - pituitary - sexual maturation
