H-1-NMR SPECTROSCOPY CAN ACCURATELY QUANTITATE THE LIPOLYSIS AND OXIDATION OF CARDIAC TRIACYLGLYCEROLS

Triacylglycerol metabolism in isolated, perfused hearts from rats fed a diet containing 20% rapeseed oil (RSO) was studied using H-1-NMR spectroscopy. RSO-induced elevation in cardiac triacylglycerols is associated with an increase in the peak area of fatty acid H-1-NMR resonances. The ratio of methyl, gamma-methylene or methylene protons adjacent to a carbon-carbon double bond to the number of methylene protons in these hearts measured by H-1-NMR spectroscopy gives values similar to those derived from previously reported chemical analyses. In addition, the triacylglycerol content of these hearts determined by chemical analysis directly correlates with their content of H-1-NMR visible fatty acid resonances. This quantitative relationship allows the real-time measurement of the rates of cardiac triacylglycerol lipolysis using H-1-NMR spectroscopy. Rates of triacylglycerol lipolysis measured using H-1-NMR spectroscopy are similar to those previously measured by chemical methods. Triacylglycerol lipolysis measured using H-1-NMR spectroscopy occurs at a significantly faster rate in hearts perfused in the presence or absence of glucose when compared to hearts perfused with glucose and acetate or medium-chain fatty acids. Finally, the rate of triacylglycerol lipolysis in glucose perfused hearts is linearly related to work output. These results demonstrate that H-1-NMR spectroscopy can accurately quantitate triacylglycerol content and metabolism in the rapeseed oil-fed rat model. H-1-NMR spectroscopic or imaging techniques may be useful in the real-time evaluation of cardiac triacylglycerol content and metabolism.