Metabolism of erucic acid in the isolated perfused rat heart

In the present work the uptake and utilization of [14C]erucic acid by the perfused rat heart has been investigated and compared with those of [14C]-palmitic acid. Both fatty acids were found to be taken up by the heart at the same rate. On the other hand, the incorporation of erucic acid into tissue lipid during 30 min perfusion were significantly high and CO2 production low as compared with palmitic acid. Incorporation of erucic acid into diacylglycerol, triacylglycerol and cholesterol ester was considerably higher than that of palmitic acid. During a 30-min period, a large amount of [14C]erucic acid was accumulated in tissue fatty acid fraction. Similarly, relatively high labelling was found in the fatty acid and diacylglycerol fraction during the initial 300 s of perfusion with erucic acid. When [14C]erucic acid and unlabelled palmitic acid was used, the radioactivity was very high in the fatty acid fraction of the heart lipid in comparison with the experiment when [14C]palmitate and unlabelled erucic acid was used. Therefore, erucic acid is poorly oxidized by the heart and is preferentially incorporated into heart lipids. There was relatively high incorporation of [14C]erucic acid into diacylglycerol and addition of unlabelled palmitic acid tended to decrease it, probably converting more diacylglycerol to triacylglycerol. When [14C]palmitic acid and erucic acid were used together, incorporation to triacylglycerol was high and diacylglycerol low. These results, therefore suggest that palmitic acid is a more suitable acyl donor than erucic acid for the C-3 position of triacylglycerol, especially when the diacylglycerol contains erucoyl moieties.