Incorporation of different fatty acids into combined lipids in rabbit atherosclerotic lesions

Abstract

14C-labelled palmitic, oleic and linoleic acids have been incubated in vitro with aortas obtained from cholesterol-fed rabbits and the relative incorporation of each of these fatty acids into cholesterol ester, phospholipid and triglyceride has been compared using gas-liquid radiochromatography. Incorporation of oleic acid into cholesterol ester is greater than that of either linoleic or palmitic acid. The amount of the individual fatty acids incorporated into triglyceride and into phospholipid, however, is roughly the same. Calculation of pool sizes indicates that the incorporation of palmitic, oleic and linoleic acid into the lipid fractions parallels the chemical amount of fatty acid in the respective lipid fraction. Differential esterification in the atherosclerotic arterial wall may, therefore, account for some of the accumulation of lipid in the lesion. Removal of the three fatty acids esterified in cholesterol ester, phospholipid and triglyceride has also been investigated in similar experiments. Intimal cholesterol ester, phospholipid and triglyceride were first labelled with palmitic, oleic and linoleic acid and then their respective specific activities followed over a subsequent incubation period. While both phospholipid and triglyceride were removed more readily than were the cholesterol esters as a group, there was no evidence to support a differential removal of different fatty acid esters within any of these groups in the atherosclerotic lesion.