BRAIN RES BULL l7(2) l4l-144, 1986.-lntracerebroventricular (lVT) administration of rat atrial peptide (6-33) (rANP) to conscious male hydrated or salt-loaded rats, resulted in significant increase in urinary volume. The diuretic effects of rANP occurred during the 3 hr period of urine collection and were most effective during the first hour. Most remarkably. rANP given IVT produced a dose-related increase in urinary sodium excretion at 3 hr. With a high dose of rANP. kaliuresis was significant only at 3 hr. Our results strongly suggest that ANF may play a significant role in central regulalion of fluid homeostasis. and that its natriuretic and diuretic effects may be. at least in paft, centrally mediated