CALL FOR PAPERS Physiological Regulation of Appetite Evaluation of interactions between CCK and GLP-1 in their effects on appetite, energy intake, and antropyloroduodenal motility in healthy men

Brennan, Ixchel M., Kate L. Feltrin, Michael Horowitz, Andre J. P. M. Smout, James H. Meyer, Judith Wishart, and Christine Feinle-Bisset. Evaluation of interactions between CCK and GLP-1 in their effects on appetite, energy intake, and antropyloroduodenal motility in healthy men. Am J Physiol Regul Integr Comp Physiol 288: R1477–R1485, 2005. First published February 3, 2005; doi:10.1152/ajpregu.00732.2004.—There is evidence that CCK and glucagon-like peptide-1 (GLP-1) mediate the effects of nutrients on appetite and gastrointestinal function and that their interaction may be synergistic. We hypothesized that intravenous CCK-8 and GLP-1 would have synergistic effects on appetite, energy intake, and antropyloroduodenal (APD) motility. Nine healthy males (age 22 1 yr) were studied on four separate days in a double-blind, randomized fashion. Appetite and APD pressures were measured during 150-min intravenous infusions of 1) isotonic saline (control), 2) CCK-8 (1.8 pmol kg 1 min ), 3) GLP-1 (0.9 pmol kg 1 min ), or 4) both CCK-8 (1.8 pmol kg 1 min ) and GLP-1 (0.9 pmol kg 1 min ). At 120 min, energy intake at a buffet meal was quantified. CCK-8, but not GLP-1, increased fullness, decreased desire to eat and subsequent energy intake, and increased the number and amplitude of isolated pyloric pressure waves and basal pyloric pressure (P 0.05). Both CCK-8 and GLP-1 decreased the number of antral and duodenal pressure waves (PWs) (P 0.05), and CCK-8 GLP-1 decreased the number of duodenal PWs more than either CCK-8 or GLP-1 alone (P 0.02). This was not the case for appetite or isolated pyloric PWs. In conclusion, at the doses evaluated, exogenously administered CCK-8 and GLP-1 had discrepant effects on appetite, energy intake, and APD pressures, and the effects of CCK-8 GLP-1, in combination, did not exceed the sum of the effects of CCK-8 and GLP-1, providing no evidence of synergism.