Acetyl-CoA carboxylase control of fatty acid oxidation in hearts from hibernating Richardson's ground squirrels
| Autor: | Gary D. Lopaschuk, Darrell D. Belke, Lawrence C.H. Wang |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Hibernation
medicine.medical_specialty Citric Acid Cycle Palmitic Acid Biophysics Down-Regulation Blood Pressure Biology behavioral disciplines and activities Biochemistry chemistry.chemical_compound Endocrinology AMP-activated protein kinase Acetyl Coenzyme A Heart Rate Internal medicine medicine Animals Cardiac Output Beta oxidation chemistry.chemical_classification Myocardium Adenylate Kinase Body Weight Fatty Acids Temperature Acetyl-CoA carboxylase Sciuridae Fatty acid Pyruvate carboxylase Isoenzymes Citric acid cycle Glucose Malonyl-CoA chemistry biology.protein Energy Metabolism Acetyl-CoA Carboxylase |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism. 1391:25-36 |
| ISSN: | 0005-2760 |
| DOI: | 10.1016/s0005-2760(97)00199-9 |
| Popis: | Although mammalian hibernators rely on stored body fat as a source of energy, direct measurement of energy substrate preference in heart tissue during hibernation, as well as potential mechanisms controlling fatty acid oxidation has not been examined. In order to determine whether an increase in fatty acid utilization occurs during hibernation, glucose and palmitate oxidation were measured in isolated working hearts from hibernating and non-hibernating Richardson's ground Squirrels. Hearts were perfused at either 37 degrees or 5 degrees C with perfusate containing 11 mM [U-14C]glucose and 1.2 mM [9,10-3H]palmitate, which allowed for direct measurement of both glucose oxidation (14CO2 production) and fatty acid oxidation (3H2O production). The contribution of fatty acid oxidation as a source of citric acid cycle acetyl-CoA was significantly greater in hearts from hibernating animals, compared to hearts from non-hibernating animals. Since acetyl-CoA carboxylase (ACC) regulates cardiac fatty acid oxidation (producing malonyl-CoA, a potent inhibitor of mitochondrial fatty acid uptake), we measured the activity and expression of ACC in these hearts. ACC activity was significantly decreased in hibernating ground squirrels, regardless of whether ACC was assayed at 37 degrees or 5 degrees C. This decrease in activity could not be explained by a change in the activity of 5'AMP-activated protein kinase, which can phosphorylate and inhibit ACC. Rather, the expression of the 280 kDa isoform of ACC (which predominates in cardiac muscle) was decreased in hearts from hibernating squirrel hearts. This suggests that a down regulation of ACC expression occurs as an adaptation for the increased utilization of fatty acid in hearts of hibernating ground squirrels. |
| Databáze: | OpenAIRE |
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