Intracerebroventricular leptin inhibits gastric emptying of a solid nutrient meal in rats

THE effects of leptin injected intracerebroventricularly (i.c.v.) or i.p. on food intake and gastric emptying of a solid nutrient meal mere studied in fasted Long-Evan rats. Leptin (3 mu g, i.c.v.) reduced the 5 h cumulative food intake by 39% and gastric transit by 50% while i.p. leptin (300 mu g) resulted in a 35% decrease in food intake and no change in gastric transit after 5 h. Lower i.p. doses of leptin (30 or 3 mu g) did not alter food intake. These results show that central, unlike peripheral, injection of leptin inhibits gastric transit of an ingested meal; such a central action of leptin may contribute to the greater potency of i.c.v. than i.p. leptin to suppress food intake. (C) 1999 Lippincott Williams & Wilkins.