Nutricion

GHRE L IN AND R EGUL ATION OF B ODY WEIGH T

PLASMA GHRELIN LEVELS AFTER DIET-INDUCED WEIGHT LOSS OR GASTRIC BYPASS SURGERY
DAVID E. CUMMINGS, M.D., DAVID S. WEIGLE,M.D., R. SCOTT FRAYO, B.S., PATRICIA A. BREEN, B.S.N., MARINA K. MA, E. PATCHEN DELLINGER, M.D., AND JONATHAN Q. PURNELL, M.D.

ABSTRACT
Background Weight loss causeschanges in appetite and energy expenditure that promote weight regain. Ghrelin is a hormone that increases food intake in rodents and humans. If circulating ghrelinparticipates in the adaptive response to weight loss, its levels should rise with dieting. Because ghrelin is produced primarily by the stomach, weight loss after gastric bypasssurgery may be accompanied by impaired ghrelin secretion. Methods We determined the 24-hour plasma ghrelin profiles, body composition, insulin levels, leptin levels, and insulinsensitivity in 13 obese subjects before and after a six-month dietary program for weight loss. The 24-hour ghrelin profiles were also determined in 5 subjects who had lostweight after gastric bypass and 10 normal-weight controls; 5 of the 13 obese subjects who participated in the dietary program were matched to the subjects in thegastricbypass group and served as obese controls. Results Plasma ghrelin levels rose sharply shortly before and fell shortly after every meal. A diet-induced weight loss of 17percent of initial body weight was associated with a 24 percent increase in the area under the curve for the 24-hour ghrelin profile (P=0.006). In contrast, despite a 36 percentweight loss after gastric bypass, the area under the curve for the ghrelin profile in the gastric-bypass group was 77 percent lower than in normal-weight controls (P