Synthesis and removal of different cholesterol esters by aortic smooth muscle cells in culture.

The incorporation of 3H-labelled oleic acid and of 14C-labelled linoleic acid into phospholipid, triglyceride and cholesterol ester in smooth muscle cells grown in incubation medium supplemented with either 5% normal or 5% hyperlipemic serum has been studied. Both fatty acids were incorporated into cholesterol esters to a greater extent when cells grown in incubation medium containing hyperlipemic serum. Oleic acid was incorporated into cholesterol esters in preference to linoleic acid. The addition of hyperlipemic serum to the incubation medium did not increase the incorporation fo either 3H-labelled oleic acid or of 14C-labelled linoleic acid into phospholipid or triglyceride. The removal of labelled lipid fractions has also been followed for four days in cells pulse labelled for 24 hours with 3H-labelled oleic acid and 14C-labelled linoleic acid. Both 3H- and 14C-labelled cholesterol esters were removed more rapidly when the smooth muscle cells were grown in medium containing normal serum than in medium containing hyperlipemic serum. The removal of both phospholipid and triglyceride was similar in normal and hyperlipemic serum. Comparison of the 3H/14C ratio indicated that the cholesterol oleate and cholesterol linoleate were removed at similar rates.