title: GIP and GLP-1(7-36)amide secretion in response to intraduodenal infusions of nutrients in pigs.
abstract: Investigation of nutrient stimulation of two gut hormones GIP (glucose dependent insulotropic polypeptide) and GLP-1(7-36)amide (the active truncated form of glucagon-like peptide-1) is made difficult by the differential control of gastric emptying. Direct nutrient infusion into the duodenum was therefore carried out on three female pigs. The infusates consisted of saline (0.85 g or 1.7 g/100 ml); glucose (20 g or 40 g/100 ml); fat (30 g or 60 g/500 ml) and glucose/fat (20 g and 30 g or 40 g and 60 g per 1000 ml). Plasma glucose levels were elevated as expected by glucose or glucose/fat infusions, and they were not affected by the presence of fat in the infusate. Insulin secretion was stimulated in the presence of glucose or glucose/fat. Plasma triacylglycerol was elevated following fat and glucose/fat infusions. The greatest stimulus for GIP secretion was glucose/fat (P < 0.05); fat alone was a poor stimulus for GIP secretion, but glucose was a potent stimulus. GLP-1(7-36)amide was moderately stimulated by glucose and markedly stimulated by fat and glucose/fat infusions (P < 0.05). We conclude that, in pigs, dual nutrient infusion of glucose/fat is a strong stimulus for both GIP and GLP-1(7-36)amide secretion. The hormones therefore have the potential to play an important physiological role, both in the stimulation of insulin secretion and in adipose tissue metabolism in pigs.
authors.affiliation: School of Biological Sciences, University of Surrey, Guildford, U.K.
authors.forename: J M
authors.initials: JM
authors.lastname: Knapper
authors.forename: A
authors.initials: A
authors.lastname: Heath
authors.forename: J M
authors.initials: JM
authors.lastname: Fletcher
authors.forename: L M
authors.initials: LM
authors.lastname: Morgan
authors.forename: V
authors.initials: V
authors.lastname: Marks
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005749:Gastric Inhibitory Polypeptide / Q000378:metabolism*; D005934:Glucagon; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D010446:Peptide Fragments / Q000378:metabolism*; D011863:Radioimmunoassay; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D013552:Swine; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin; D010446:Peptide Fragments; D014280:Triglycerides; C055453:glucagon-like peptide 1 (7-36)amide; D012965:Sodium Chloride; D005749:Gastric Inhibitory Polypeptide; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D005947:Glucose