The gut-derived incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are known for insulinotropic and glucose-lowering effects. However, their individual roles in postprandial glucose homeostasis are unknown. We infused the GIP receptor antagonist GIP(3-30)NH2 and the GLP-1 receptor antagonist exendin(9-39) during a meal to determine the roles of endogenous GIP and GLP-1 on postprandial glucose metabolism. On four separate days, 12 healthy men (age 19-65 years, BMI 20-25 kg/m2) received a liquid mixed meal test with randomized and double-blinded infusions of GIP(3-30)NH2 (800 pmol/kg/min) + Ex(9-39) (450 pmol/kg/min) (A), GIP(3-30)NH2 (B), Ex(9-39) (C), and saline (D). On Day A, B and C, glucose excursions were significantly increased by 85%, 55% and 15%, respectively, compared to D. Day A and B excursions were significantly higher than C (Figure). Glucagon levels at 60 min differed between Day A and B (11.5±1.2 vs. 7.5±0.6 pmol/l, P=0.01), and Day B and C (11.5±1.2 vs. 12.9±1.5 pmol/l, P=0.008). GLP-1 was higher on Day A (P=0.01) and C (P=0.02) than D. No significant effects on insulin, C-peptide, gastric emptying, or GIP were observed. We conclude that endogenous GIP affects postprandial plasma glucose excursions more pronouncedly than GLP-1, and that both hormones additively contribute to control postprandial glycemia in healthy subjects.
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Disclosure

L.S. Gasbjerg: Stock/Shareholder; Self; Antag Therapeutics. M.M. Helsted: None. A.H. Sparre-Ulrich: Employee; Self; Antag Therapeutics ApS. A.R. Lanng: None. S. Stensen: None. M. Jakobsen: None. B. Hartmann: None. M.B. Christensen: None. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S. Board Member; Self; Zealand Pharma A/S. Speaker's Bureau; Self; Merck Sharp & Dohme Corp., AstraZeneca. Research Support; Self; Danish Diabetes Academy, Novo Nordisk Foundation. Other Relationship; Self; Antag Therapeutics. Other Relationship; Spouse/Partner; Antag Therapeutics. T. Vilsbøll: Advisory Panel; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Consultant; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Speaker's Bureau; Self; Amgen Inc., Boehringer Ingelheim GmbH, Eli Lilly and Company, AstraZeneca, MSD K.K., Sanofi, Novo Nordisk A/S. Research Support; Self; Eli Lilly and Company, Novo Nordisk A/S. M.M. Rosenkilde: Other Relationship; Self; Antag Therapeutics. Advisory Panel; Spouse/Partner; Novo Nordisk A/S. Board Member; Spouse/Partner; Zealand Pharma A/S. Speaker's Bureau; Spouse/Partner; Merck Sharp & Dohme Corp., AstraZeneca. Research Support; Spouse/Partner; Danish Diabetes Academy, Novo Nordisk Foundation. Other Relationship; Spouse/Partner; Antag Therapeutics. F.K. Knop: Advisory Panel; Self; AstraZeneca. Consultant; Self; AstraZeneca. Research Support; Self; AstraZeneca. Speaker's Bureau; Self; AstraZeneca. Advisory Panel; Self; Eli Lilly and Company. Speaker's Bureau; Self; Eli Lilly and Company. Advisory Panel; Self; Amgen Inc.. Speaker's Bureau; Self; Merck Sharp & Dohme Corp.. Advisory Panel; Self; Novo Nordisk A/S. Consultant; Self; Novo Nordisk A/S. Speaker's Bureau; Self; Novo Nordisk A/S. Consultant; Self; Amgen Inc.. Advisory Panel; Self; MedImmune, Sanofi. Consultant; Self; Sanofi. Research Support; Self; Sanofi. Speaker's Bureau; Self; Sanofi.

© 2018 by the American Diabetes Association.
2018
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