title: Intraduodenal protein modulates antropyloroduodenal motility, hormone release, glycemia, appetite, and energy intake in lean men.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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 = -0.51, P < 0.001).
  
  
  CONCLUSIONS
  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. This trial was registered at www.anzctr.org.au as 12610000376044.
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: Amy T
authors.initials: AT
authors.lastname: Ryan
authors.forename: Christine
authors.initials: C
authors.lastname: Feinle-Bisset
authors.forename: Asimina
authors.initials: A
authors.lastname: Kallas
authors.forename: Judith M
authors.initials: JM
authors.lastname: Wishart
authors.forename: Peter M
authors.initials: PM
authors.lastname: Clifton
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Natalie D
authors.initials: ND
authors.lastname: Luscombe-Marsh
mesh_terms: D000328:Adult; D001069:Appetite Regulation; D001786:Blood Glucose / Q000032:analysis; D018592:Cross-Over Studies; D004044:Dietary Proteins / Q000008:administration & dosage*; D004311:Double-Blind Method; D004386:Duodenum / Q000378:metabolism / Q000502:physiology*; D002149:Energy Intake; D005768:Gastrointestinal Hormones / Q000097:blood* / Q000378:metabolism; D005769:Gastrointestinal Motility; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D008894:Milk Proteins / Q000008:administration & dosage; D009520:New Zealand; D019518:Postprandial Period; D011492:Protein Hydrolysates / Q000008:administration & dosage; D011706:Pyloric Antrum / Q000502:physiology*; D000067816:Whey Proteins; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D004044:Dietary Proteins; D005768:Gastrointestinal Hormones; D007328:Insulin; D008894:Milk Proteins; D011492:Protein Hydrolysates; D000067816:Whey Proteins