TY - JOUR

T1 - The incretin effect does not differ in trained and untrained, young, healthy men

AU - Lund, Michael Taulo

AU - Dalby, Sina

AU - Hartmann, Bolette

AU - Helge, Jørn Wulff

AU - Holst, Jens Juul

AU - Dela, Flemming

N1 - © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

PY - 2014/3

Y1 - 2014/3

N2 - Aim: After both oral and intravenous glucose administration, peripheralinsulin concentrations are lower in trained compared with untrainedhumans. Part of this is explained by an adaptation within the b-cell. Theinsulin secretion rate is higher after oral compared with intravenous glucoseadministration due to the release of glucagon-like peptide-1 (GLP-1)and glucose-dependent insulinotropic polypeptide (GIP) enhancing the glucose-induced insulin secretion (the incretin effect). Our aim was to investigatewhether GIP or GLP-1 release or the incretin effect was different intrained compared with untrained humans after oral and intravenousglucose administration.Methods: A 3½-h oral glucose tolerance test was performed in eleventrained and ten untrained, young, healthy men. On a separate day, an isoglycaemicintravenous glucose infusion was performed matching the individualglucose concentrations obtained during the oral glucose tolerancetest. Blood samples for insulin, C-peptide, GIP and GLP-1 analyses wereobtained frequently during both tests, and the insulin secretion rate, incretineffect and insulin clearance were calculated.Results: Plasma GIP and GLP-1 concentrations, the incretin effect and theinsulin clearance did not differ, and plasma glucose, insulin and C-peptideconcentrations and the insulin secretion rate were lower in trained comparedwith untrained subjects during both tests.Conclusion: With no difference in incretin effect and insulin clearancebetween the two groups, the lower plasma insulin concentrations found intrained compared with untrained, young, healthy men are most likelyexplained by lower b-cell sensitivity to glucose and enhanced glucoseuptake in skeletal muscle in the former group.

AB - Aim: After both oral and intravenous glucose administration, peripheralinsulin concentrations are lower in trained compared with untrainedhumans. Part of this is explained by an adaptation within the b-cell. Theinsulin secretion rate is higher after oral compared with intravenous glucoseadministration due to the release of glucagon-like peptide-1 (GLP-1)and glucose-dependent insulinotropic polypeptide (GIP) enhancing the glucose-induced insulin secretion (the incretin effect). Our aim was to investigatewhether GIP or GLP-1 release or the incretin effect was different intrained compared with untrained humans after oral and intravenousglucose administration.Methods: A 3½-h oral glucose tolerance test was performed in eleventrained and ten untrained, young, healthy men. On a separate day, an isoglycaemicintravenous glucose infusion was performed matching the individualglucose concentrations obtained during the oral glucose tolerancetest. Blood samples for insulin, C-peptide, GIP and GLP-1 analyses wereobtained frequently during both tests, and the insulin secretion rate, incretineffect and insulin clearance were calculated.Results: Plasma GIP and GLP-1 concentrations, the incretin effect and theinsulin clearance did not differ, and plasma glucose, insulin and C-peptideconcentrations and the insulin secretion rate were lower in trained comparedwith untrained subjects during both tests.Conclusion: With no difference in incretin effect and insulin clearancebetween the two groups, the lower plasma insulin concentrations found intrained compared with untrained, young, healthy men are most likelyexplained by lower b-cell sensitivity to glucose and enhanced glucoseuptake in skeletal muscle in the former group.

KW - Faculty of Health and Medical Sciences

KW - Incretin

KW - insulin

KW - GLP-1

KW - GIP

KW - Exercise

KW - Training

KW - Glucose

U2 - 10.1111/apha.12218

DO - 10.1111/apha.12218

M3 - Journal article

C2 - 24354574

VL - 210

SP - 565

EP - 572

JO - Acta Physiologica

JF - Acta Physiologica

SN - 1748-1708

IS - 3

ER -