Effects of prior exercise on the action of insulin-like growth factor I in skeletal muscle

E. J. Henriksen, L. L. Louters, C. S. Stump, C. M. Tipton

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Prior exercise increases insulin sensitivity for glucose and system A neutral amino acid transport activities in skeletal muscle. Insulin-like growth factor I (IGF-I) also activates these transport processes in resting muscle. It is not known, however, whether prior exercise increases IGF-I action in muscle. Therefore we determined the effect of a single exhausting bout of swim exercise on IGF-I-stimulated glucose transport activity [assessed by 2-deoxy-D-glucose (2-DG) uptake] and system A activity [assessed by α-(methylamino)isobutyric acid (MeAIB) uptake] in the isolated rat epitrochlearis muscle. When measured 3.5 h after exercise, the responses to a submaximal concentration (0.2 nM), but not a maximal concentration (13.3 nM), of insulin for activation of 2-DG uptake and MeAIB uptake were enhanced. In contrast, prior exercise increased markedly both the submaximal (5 nM) and maximal (20 nM) responses to IGF-I for activation of 2-DG uptake, whereas only the submaximal response to IGF-I (3 nM) for MeAIB uptake was enhanced after exercise. We conclude that 1) prior exercise significantly enhances the response to a submaximal concentration of IGF-I for activation of the glucose transport and system A neutral amino acid transport systems in skeletal muscle and 2) the enhanced maximal response for IGF-I action after exercise is restricted to the signaling pathway for activation of the glucose transport system.

Original languageEnglish (US)
Pages (from-to)E340-E344
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume263
Issue number2 26-2
DOIs
StatePublished - 1992

Keywords

  • 2-deoxy-D-glucose uptake
  • epitrochlearis muscle
  • insulin action
  • swim exercise
  • α-(methylamino)isobutyric acid uptake

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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