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Regulation of fatty acid oxidation of the heart by MCD and ACC during contractile stimulation.

Authors: Goodwin, GW  Taegtmeyer, H 
Citation: Goodwin GW and Taegtmeyer H, Am J Physiol. 1999 Oct;277(4 Pt 1):E772-7.
Pubmed: (View Article at PubMed) PMID:10516138

We tested the hypothesis that the level of malonyl-CoA, as well as the corresponding rate of total fatty acid oxidation of the heart, is regulated by the opposing actions of acetyl-CoA carboxylase (ACC) and malonyl-CoA decarboxylase (MCD). We used isolated working rat hearts perfused under physiological conditions. MCD in heart homogenates was measured specifically by (14)CO(2) production from [3-(14)C]malonyl-CoA, and ACC was measured specifically based on the portion of total carboxylase that is citrate sensitive. Increased heart work (1 microM epinephrine + 40% increase in afterload) elicited a 40% increase in total beta-oxidation of exogenous plus endogenous lipids, accompanied by a 33% decrease in malonyl-CoA. The basal activity and citrate sensitivity of ACC (reflecting its phosphorylation state) and citrate content were unchanged. AMP levels were also unchanged. MCD activity, when measured at a subsaturating concentration of malonyl-CoA (50 microM), was increased by 55%. We conclude that physiological increments in AMP during the work transition are insufficient to promote ACC phosphorylation by AMP-stimulated protein kinase. Rather, increased fatty acid oxidation results from increased malonyl-CoA degradation by MCD.

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RGD Object Information
RGD ID: 1600797
Created: 2007-03-27
Species: All species
Last Modified: 2007-03-27
Status: ACTIVE



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