Ampk and Metabolic Adaptation by the Heart to Pressure Overload.
From: James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Rm 166, St. Paul’s Hospital, 1081 Burrard St., Vancouver, BC, Canada. mallard@mrl.ubc.ca
American journal of physiology. Heart and circulatory physiology
- Publish Date: Jan 2007
- ISSN: 0363-6135
- Volume: 292
- Issue: 1
- Pages: H140-8
- Medium: Print
- Language: English
- Citation (JAMA): Allard Michael F, Parsons Hannah L, Saeedi Ramesh, et al. Ampk and Metabolic Adaptation by the Heart to Pressure Overload.. Am. J. Physiol. Heart Circ. Physiol. Jan 2007;292:H140-8
Abstract
Accelerated glycolysis in hypertrophied hearts may be a compensatory response to reduced energy production from long-chain fatty acid oxidation with 5’-AMP-activated protein kinase (AMPK) functioning as a cellular signal. Therefore, we tested the hypothesis that enhanced fatty acid oxidation improves energy status and normalizes AMPK activity and glycolysis in hypertrophied hearts. Glycolysis, fatty acid oxidation, AMPK activity, and energy status were measured in isolated working hypertrophied and control hearts from aortic-constricted and sham-operated male Sprague-Dawley rats. Hearts from halothane (3-4%)-anesthetized rats were perfused with KH solution containing either palmitate, a long-chain fatty acid, or palmitate plus octanoate, a medium-chain fatty acid whose oxidation is not impaired in hypertrophied hearts. Compared with control, fatty acid oxidation was lower in hypertrophied hearts perfused with palmitate, whereas it increased to similar values in both groups with octanoate plus palmitate. Glycolysis was accelerated in palmitate-perfused hypertrophied hearts and was normalized in hypertrophied hearts by the addition of octanoate. AMPK activity was increased three- to sixfold with palmitate alone and was reduced to control values by octanoate plus palmitate. Myocardial energy status improved with the addition of octanoate but did not differ between groups. Our findings, particularly the correspondence between glycolysis and AMPK activity, provide support for the view that activation of AMPK is responsible, in part, for the acceleration of glycolysis in cardiac hypertrophy. Additionally, they indicate myocardial AMPK is activated by energy state-independent mechanisms in response to pressure overload, demonstrating AMPK is more than a sensor of the heart’s energy status.
Mesh Headings (Keywords): Adaptation, Physiological, Animals, Blood Pressure, Energy Metabolism, Fatty Acids, Heart, Hypertrophy, Left Ventricular, Male, Multienzyme Complexes, Protein-Serine-Threonine Kinases, Rats, Rats, Sprague-Dawley
Check for Full Text / PubMed Unique Identifier (PMID): 16920812
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