Effect of methionine on the fatty acid composition of cellular membranes in rats with chronic ethanol consumption and jejunoileal bypass

Abstract

The objective of this study was to investigate the effect of alcohol administration on jejunoileal bypass (JIB)-induced liver dysfunction in rats resulting in abnormalities of fatty acid composition of cell membranes, and whether methionine is able to reverse these changes. Male Wistar rats were subjected to a jejunoileal bypass operation. For 12 weeks, all groups were pair-fed either an alcohol-containing (36% of total calories) liquid diet or a liquid diet in which alcohol was replaced isocalorically by starch. Methionine supplementation in three control groups was 0, 32 and 160 mg/kg body weight/day and the rats in the four alcohol feeding groups received 0, 32, 160 and 224 mg/kg body weight/day. In the alcohol group without any methionine supplementation, higher proportions of oleic and linoleic acid and lower proportions of docosahexaenoic and arachidonic acid became evident in tissue samples of liver and jejunum, in comparison with the other alcohol group. A possible explanation for this reduction in tissue polyunsaturated fatty acid (PUFA) may be a decrease in the activities of Δ6- and Δ5-desaturases, and subsequently a displacement of PUFA from lipid fractions by other fatty acids. Interestingly, in the alcohol group with the highest methionine supplementation, compared to all other alcohol groups, lower proportions of oleic acid, and higher proportions of docosahexaenoic acid, appeared. A possible explanation for this increase of PUFA in tissue map be increased activities of Δ6- and Δ5-desaturases.