title: Regional specificity of the gut-incretin response to small intestinal glucose infusion in healthy older subjects.
abstract: The importance of the region, as opposed to the length, of small intestine exposed to glucose in determining the secretion of the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) remains unclear. We sought to compare the glycemic, insulinemic and incretin responses to glucose administered to the proximal (12-60cm beyond the pylorus), or more distal (>70cm beyond the pylorus) small intestine, or both. 10 healthy subjects (9M,1F; aged 70.3±1.4years) underwent infusion of glucose via a catheter into the proximal (glucose proximally; GP), or distal (glucose distally; GD) small intestine, or both (GPD), on three separate days in a randomised fashion. Blood glucose, serum insulin and plasma GLP-1, GIP and CCK responses were assessed. The iAUC for blood glucose was greater in response to GPD than GP (P<0.05), with no difference between GD and GP. GP was associated with minimal GLP-1 response (P=0.05), but substantial increases in GIP, CCK and insulin (P<0.001 for all). GPD and GD both stimulated GLP-1, GIP, CCK and insulin (P<0.001 for all). Compared to GP, GPD induced greater GLP-1, GIP and CCK responses (P<0.05 for all). Compared with GPD, GD was associated with greater GLP-1 (P<0.05), but reduced GIP and CCK (P<0.05 for both), responses. We conclude that exposure of glucose to the distal small intestine appears necessary for substantial GLP-1 secretion, while exposure of both the proximal and distal small intestine result in substantial secretion of GIP.
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Rachael S
authors: RS
authors: Rigda
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Laurence G
authors: LG
authors: Trahair
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Tanya J
authors: TJ
authors: Little
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Tongzhi
authors: T
authors: Wu
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Scott
authors: S
authors: Standfield
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Christine
authors: C
authors: Feinle-Bisset
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Christopher K
authors: CK
authors: Rayner
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia.
authors: Michael
authors: M
authors: Horowitz
authors: Discipline of Medicine, The University of Adelaide, South Australia, 5000, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, South Australia, 5000, Australia. Electronic address: karen.jones@adelaide.edu.au.
authors: Karen L
authors: KL
authors: Jones
mesh_terms: D000368:Aged; D001786:Blood Glucose; D002766:Cholecystokinin / Q000097:blood; D004386:Duodenum / Q000187:drug effects*; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D054795:Incretins / Q000097:blood*; D007328:Insulin / Q000097:blood; D008297:Male; D009928:Organ Specificity
chemical_list: D001786:Blood Glucose; D054795:Incretins; D007328:Insulin; D052216:Glucagon-Like Peptide 1; D002766:Cholecystokinin; D005947:Glucose
keywords: Glucagon-like peptide-1; Glucose; Glucose-dependent insulinotropic polypeptide; Incretin; Older subjects