Leptin(116-130) enhances the proliferative activity of immature rat adrenal cortex

We have investigated the effects of three subcutaneous injections of 2 nmol /100 g body weight of native murine leptin(1-147) and its biological active fragment 16-130 on the proliferative activity of the zona glomerulosa (ZG) of adult (2-month-old) and immature (20-day-old) rats. Neither leptin alte red the ZG mitotic index (parts per thousand of metaphase-arrested cells) i n adult rats. Leptin(116-130) evoked a 40% rise in the mitotic index in imm ature rat ZG, while leptin(1-147) was ineffective. We concluded that leptin fragment 116-130 exerts a promoting effect on the growth Of immature rat a drenals, whose physiological relevance remains to be established. Med Sci R es 27:675-676 (C) 1999 Lippincott Williams & Wilkins.