Hutchison, A.Feinle-Bisset, C.Kallas, A.Wishart, J.Clifton, P.Horowitz, M.Luscombe-Marsh, N.2012-10-172012-10-172012American Journal of Clinical Nutrition, 2012; 96(3):474-4820002-91651938-3207http://hdl.handle.net/2440/73612BACKGROUND: Intraduodenal fat and carbohydrate modulate antropyloroduodenal motility and hormone release and suppress appetite and energy intake in a load-dependent manner. Protein also suppresses energy intake, but its effects on these gastrointestinal factors and their role in the appetite-suppressive effects of protein remain unclear. OBJECTIVE: We aimed to characterize the effects of different intraduodenal protein loads on antropyloroduodenal pressures, gastrointestinal hormone release, glucose and insulin concentrations, appetite perceptions, and energy intake. DESIGN: Sixteen lean, healthy men were studied on 4 occasions in a randomized, double-blind fashion. Antropyloroduodenal pressures, plasma glucagon-like peptide 1 (GLP-1), cholecystokinin, peptide YY, ghrelin, blood glucose, serum insulin, and appetite were measured during 60-min, 4-mL/min intraduodenal infusions of protein at 0.5, 1.5, or 3 kcal/min or saline (control). Energy intakes at a buffet lunch consumed immediately after the infusion were quantified. RESULTS: Increases in the load of protein resulted in greater suppression of antral motility, greater stimulation of basal and isolated pyloric pressures and plasma cholecystokinin and GLP-1 concentrations, and greater suppression of energy intake. However, energy intake was reduced only after a protein load of 3 kcal/min compared with after all other treatments (P< 0.05). The suppression of energy intake after adjustment for cholecystokinin, GLP-1, and insulin was related inversely with basal pyloric pressure (r = 20.51, P < 0.001). CONCLUSION: The acute effects of intraduodenal protein on antropyloroduodenal motility, gastrointestinal hormone release, glucose, and insulin are load dependent and contribute to the suppression of energy intake.en© 2012 American Society for NutritionDuodenumPyloric AntrumHumansGastrointestinal HormonesInsulinBlood GlucoseDietary ProteinsMilk ProteinsProtein HydrolysatesCross-Over StudiesDouble-Blind MethodEnergy IntakeAppetite RegulationGastrointestinal MotilityPostprandial PeriodAdultMiddle AgedNew ZealandMaleYoung AdultWhey ProteinsJournal article002012178710.3945/ajcn.112.0381330003078638000052-s2.0-8486534082423292Hutchison, A. [0000-0002-6393-3671]Feinle-Bisset, C. [0000-0001-6848-0125]Clifton, P. [0000-0002-6411-626X]Horowitz, M. [0000-0002-0942-0306]Luscombe-Marsh, N. [0000-0001-9690-4722]