title: Comparative effects of intraduodenal whey protein hydrolysate on antropyloroduodenal motility, gut hormones, glycemia, appetite, and energy intake in lean and obese men.
abstract: In lean individuals, intraduodenal protein and lipid modulate gastrointestinal motor and hormone functions and reduce energy intake in a load-dependent manner; protein also stimulates insulin, with modest effects on reducing blood glucose. The effect of intraduodenal lipid on gastrointestinal motor and hormone responses is diminished in obesity; whether the effects of protein are also attenuated remains unclear.
  
  
  
  The objectives of this study were to characterize the load-dependent effects of intraduodenal whey protein hydrolysate on antropyloroduodenal pressures, gut hormones, glycemia, appetite, and energy intake in obese subjects and to compare the responses to the higher protein load with those in lean subjects.
  
  
  
  We measured antropyloroduodenal pressures, plasma cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), glucagon, insulin, blood glucose, appetite, and energy intake in 12 nondiabetic obese men on 3 separate occasions, in a double-blind, randomized order, during 60-min intraduodenal infusions of hydrolyzed whey protein at either 0 (saline control), 1.5, or 3 kcal/min. Twelve age-matched lean individuals received a 3-kcal/min infusion only. Immediately after the infusions, energy intake from a buffet lunch was quantified.
  
  
  
  In obese subjects, protein suppressed antral and duodenal pressures; stimulated plasma CCK, GLP-1, GIP, insulin, and glucagon (all r > 0.57, P < 0.01); and tended to reduce energy intake (r = -10.38, P = 0.057) in a dose-dependent manner. In response to the 3-kcal/min protein load, antropyloroduodenal pressures, CCK, GLP-1, and glucagon did not differ between lean and obese subjects. Insulin release was greater, and GIP release less, in obese than in lean subjects (both P < 0.05), whereas the reduction in glucose was comparable. Energy intake tended to be higher in obese subjects (P = 0.08).
  
  
  
  The gastrointestinal effects of hydrolyzed whey protein remain relatively intact in obesity; however, the observed changes in insulin and GIP suggest early disturbances in the insulin-incretin axis. This study was registered at www.anzctr.org.au as ACTRN 12612000203853.
authors.affiliation: University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Amy T
authors.identifier: 0000-0002-6393-3671
authors.initials: AT
authors.lastname: Hutchison
authors.affiliation: University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Christine
authors.identifier: 0000-0001-6848-0125
authors.initials: C
authors.lastname: Feinle-Bisset
authors.affiliation: University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Penelope C E
authors.initials: PC
authors.lastname: Fitzgerald
authors.affiliation: University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Scott
authors.initials: S
authors.lastname: Standfield
authors.affiliation: University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.affiliation: University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia; School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia; and.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Clifton
authors.affiliation: University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia; Commonwealth Scientific and Industrial Research Organization, Animal, Food and Health Sciences, Adelaide, Australia natalie.luscombe-marsh@csiro.au.
authors.forename: Natalie D
authors.identifier: 0000-0001-9690-4722
authors.initials: ND
authors.lastname: Luscombe-Marsh
mesh_terms: D000293:Adolescent; D000328:Adult; D001069:Appetite Regulation; D015992:Body Mass Index; D004311:Double-Blind Method; D004386:Duodenum / Q000378:metabolism / Q000503:physiopathology*; D002149:Energy Intake; D004750:Enteral Nutrition; D005753:Gastric Mucosa / Q000378:metabolism / Q000503:physiopathology; D005768:Gastrointestinal Hormones / Q000097:blood / Q000378:metabolism; D005769:Gastrointestinal Motility; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000503:physiopathology; D007441:Intubation, Gastrointestinal; D062409:Lunch; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D011492:Protein Hydrolysates / Q000008:administration & dosage / Q000627:therapeutic use*; D011706:Pyloric Antrum / Q000378:metabolism / Q000503:physiopathology*; D000067816:Whey Proteins / Q000008:administration & dosage / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D005768:Gastrointestinal Hormones; D011492:Protein Hydrolysates; D000067816:Whey Proteins
keywords: blood glucose; cholecystokinin; food intake; gastrointestinal motility; glucagon-like peptide 1; obesity