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 spe ctroscopy. RSO-induced elevation in cardiac triacylglycerols is associ ated with an increase in the peak area of fatty acid H-1-NMR resonance s. The ratio of methyl, gamma-methylene or methylene protons adjacent to a carbon-carbon double bond to the number of methylene protons in t hese hearts measured by H-1-NMR spectroscopy gives values similar to t hose derived from previously reported chemical analyses. In addition, the triacylglycerol content of these hearts determined by chemical ana lysis directly correlates with their content of H-1-NMR visible fatty acid resonances. This quantitative relationship allows the real-time m easurement 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 chemic al methods. Triacylglycerol lipolysis measured using H-1-NMR spectrosc opy occurs at a significantly faster rate in hearts perfused in the pr esence or absence of glucose when compared to hearts perfused with glu cose and acetate or medium-chain fatty acids. Finally, the rate of tri acylglycerol lipolysis in glucose perfused hearts is linearly related to work output. These results demonstrate that H-1-NMR spectroscopy ca n accurately quantitate triacylglycerol content and metabolism in the rapeseed oil-fed rat model. H-1-NMR spectroscopic or imaging technique s may be useful in the real-time evaluation of cardiac triacylglycerol content and metabolism.