Changes in fatty acid composition of myocardial triglyceride following a single administration of ethanol to rabbits

Abstract

Even a moderate does of alcohol infused into fasted and fed rabbits (1.95 g/kg for over 2 h) induces a change in myocardial lipid metabolism. Such metabolic alterations were studied by measuring fatty acid oxidation and esterification by homogenates prepared from the hearts of these rabbits, and also by analyzing fatty acid composition of heart triglyceride. Ethanol administration resulted in depressed fatty acid oxidation and enhanced esterification. These metabolic derangements were restored towards the control value by the addition of carnitine in the incubation medium. The fatty acid analysis using gas chromatography was performed with rabbit heart triglyceride, adipose tissue, plasma FFA and rabbit food, each of them showing a slightly different composition. Ethanol was infused into either fed or fasted animals and the fatty acid composition of cardiac triglyceride was examined. There was very little difference in ethanol-induced compositional changes between the two dietary states of the animals, although in both instances the content of heart triglyceride was increased three hours after cessation of ethanol infusion. However, fatty acid composition of heart triglyceride greatly changed and showed a close resemblance to that of the plasma FFA, suggesting that the source of the increased fatty acid moiety in the myocardium is plasma FFA and that heart triglyceride undergoes turnover at a considerably high rate. However, this altered composition of cardiac triglyceride returned towards the pre-infusion pattern at a very slow pace. In particular, unsaturated fatty acid levels did not rise to the control value during a 2-week observation period, indicating that transacylation and desaturation processes in the organ, as well as re-arrangement or exchange of the acyl moiety of complex lipids among organs, are gradual.