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

M T Lund, Sina Dalby, B Hartmann, J W Helge, J J Holst, F Dela

11 Citations (Scopus)

Abstract

AIM: After both oral and intravenous glucose administration, peripheral insulin concentrations are lower in trained compared with untrained humans. Part of this is explained by an adaptation within the β-cell. The insulin secretion rate is higher after oral compared with intravenous glucose administration 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 investigate whether GIP or GLP-1 release or the incretin effect was different in trained compared with untrained humans after oral and intravenous glucose administration.

METHODS: A 3½-h oral glucose tolerance test was performed in eleven trained and ten untrained, young, healthy men. On a separate day, an isoglycaemic intravenous glucose infusion was performed matching the individual glucose concentrations obtained during the oral glucose tolerance test. Blood samples for insulin, C-peptide, GIP and GLP-1 analyses were obtained frequently during both tests, and the insulin secretion rate, incretin effect and insulin clearance were calculated.

RESULTS: Plasma GIP and GLP-1 concentrations, the incretin effect and the insulin clearance did not differ, and plasma glucose, insulin and C-peptide concentrations and the insulin secretion rate were lower in trained compared with untrained subjects during both tests.

CONCLUSION: With no difference in incretin effect and insulin clearance between the two groups, the lower plasma insulin concentrations found in trained compared with untrained, young, healthy men are most likely explained by lower β-cell sensitivity to glucose and enhanced glucose uptake in skeletal muscle in the former group.

Original languageEnglish
JournalActa physiologica (Oxford, England)
Volume210
Issue number3
Pages (from-to)565-72
Number of pages8
ISSN1748-1708
DOIs
Publication statusPublished - Mar 2014

Keywords

  • Adult
  • Blood Glucose
  • Gastric Inhibitory Polypeptide
  • Glucagon-Like Peptide 1
  • Glucose
  • Glucose Tolerance Test
  • Humans
  • Incretins
  • Insulin
  • Male
  • Physical Fitness
  • Young Adult
  • Journal Article
  • Research Support, Non-U.S. Gov't

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