Alteration of rat heart sarcolemma lipid composition by dietary elaidic acid.

Male weanling rats were fed a semisynthetic diet containing 5% of either elaidic acid or oleic acid for 4 weeks. The heart sarcolemma were isolated and examined for purity by using marker enzymes. The sarcolemma preparations were enriched in phosphodiesterase I, 5'-nucleotidase and p-nitrophenyl phosphatase as compared with the heart homogenates. Succinic dehydrogenase activity was not detected in these preparations. The lipids of sarcolemma fractions from animals fed the trans fatty acids were enriched with the fatty acid fed. Most of this incorporation was found to be associated with the two major phospholipids, phosphatidylcholine and phosphatidylethanolamine. The incorporation of elaidic acid into the membranes resulted in an increase in membrane cholesterol without affecting either membrane phospholipid content or profile. The alterations induced in the lipid composition of heart sarcolemma by feeding this dietary trans fatty acid suggest some functional alterations in these membranes.