Academic Article


  • 2010

Lai YC, Zarrinpashneh E, Jensen J. Additive effect of contraction and insulin on glucose uptake and glycogen synthase in muscle with different glycogen contents. J Appl Physiol 108: 1106-1115, 2010. First published February 25, 2010; doi:10.1152/japplphysiol.00401.2009.-Insulin and contraction regulate glucose uptake and glycogen synthase (GS) via distinct mechanisms in skeletal muscles, and an additive effect has been reported. Glycogen content is known to influence both contraction- and insulin-stimulated glucose uptake and GS activity. Our study reports that contraction and insulin additively stimulate glucose uptake in rat epitrochlearis muscles with normal (NG) and high (HG) glycogen contents, but the additive effect was only partial. In muscles with low glycogen (LG) content no additive effect was seen, but glucose uptake was higher in LG than in NG and HG during contraction, insulin stimulation, and when the two stimuli were combined. In LG, contraction-stimulated AMP-activated protein kinase (AMPK) activity and insulin-stimulated PKB phosphorylation were higher than in NG and HG, but phosphorylation of Akt substrate of 160 kDa was not elevated correspondingly. GLUT4 content was 50% increased in LG (rats fasted 24 h), which may explain the increased glucose uptake. Contraction and insulin also additively increased GS fractional activity in NG and HG...

Lai, Yu-Chiang; Zarrinpashneh, Elham; Jensen, Jørgen
Journal of applied physiology American Physiological Society, Journal of applied physiology 108(5): 1106–1115
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