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Effect of short-term exercise training on insulin-stimulated PI 3-kinase activity in human skeletal muscle

journal contribution
posted on 1999-12-01, 00:00 authored by J A Houmard, Chris ShawChris Shaw, M S Hickey, C J Tanner
The purpose of this study was to determine if the improvement in insulin sensitivity with exercise training is associated with enhanced phosphatidylinositol 3-kinase (PI 3-kinase) activity. Nine sedentary men were studied before and after 7 days of exercise training (1 h/day, ≃75% maximal oxygen consumption). Insulin sensitivity was determined with a euglycemic- hyperinsulinemic glucose clamp in the sedentary state and 15-17 h after the final exercise bout. PI 3-kinase activity was determined from samples (vastus lateralis) obtained in the fasted condition and after 60 min of submaximal insulin stimulation during the clamp. After exercise, glucose infusion rate increased (P 0.05) significantly (means ± SE, 7.8 ± 0.5 vs. 9.8 ± 0.8 mg·kg-1·min-1), indicating improved insulin sensitivity. Insulin- stimulated (insulin stimulated/fasting) phosphotyrosine immunoprecipitable PI 3-kinase activity also increased significantly (P < 0.05) with exercise (3.1 ± 0.8-fold) compared with the sedentary condition (1.3 ± 0.1-fold). There was no change in fasting PI 3-kinase activity. These data suggest that an enhancement of insulin signal transduction in skeletal muscle may contribute to the improvement in insulin action with exercise.

History

Journal

American journal of physiology - endocrinology and metabolism

Volume

277

Issue

6

Publisher

American Physiological Society

Location

Bethesda, Md.

ISSN

0193-1849

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1999, American Physiological Society

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