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Media type:
E-Article
Title:
Inactivation of acetyl-CoA carboxylase and activation of AMP-activated protein kinase in muscle during exercise
Contributor:
Winder, W. W.;
Hardie, D. G.
Published:
American Physiological Society, 1996
Published in:
American Journal of Physiology-Endocrinology and Metabolism, 270 (1996) 2, Seite E299-E304
Language:
English
DOI:
10.1152/ajpendo.1996.270.2.e299
ISSN:
0193-1849;
1522-1555
Origination:
Footnote:
Description:
<jats:p> Malonyl-CoA, an inhibitor of fatty acid oxidation in skeletal muscle mitochondria, decreases in rat skeletal muscle during exercise or in response to electrical stimulation. Regulation of rat skeletal muscle acetyl-CoA carboxylase (ACC), the enzyme that synthesizes malonyl-CoA, was studied in vitro and in vivo. Avidin-Sepharose affinity-purified ACC from hindlimb skeletal muscle was phosphorylated by purified liver AMP-activated protein kinase with a concurrent decrease in ACC activity. AMP-activated protein kinase was quantitated in resuspended ammonium sulfate precipitates of the fast-twitch red (type IIa fibers) region of the quadriceps muscle. Rats running on a treadmill at 21 m/min up a 15% grade show a 2.4-fold activation of AMP-activated protein kinase concurrently with a marked decrease in ACC activity in the resuspended ammonium sulfate precipitates at all citrate concentrations ranging from 0 to 20 mM. Malonyl-CoA decreased from a resting value of 1.85 +/- 0.29 to 0.50 +/- 0.09 nmol/g in red quadriceps muscle after 30 min of treadmill running. The activation of the AMP-activated protein kinase with consequent phosphorylation and inactivation of ACC may be one of the primary events in the control of malonyl-CoA and hence fatty acid oxidation during exercise. </jats:p>