Removal of fatty acid labelled cholesterol ester, phospholipid and triglyceride from atherosclerotic rabbit aorta in vitro.

An organ culture technique was used to investigate the removal of fatty acids incorporated into various lipid fractions in intimal segments of atherosclerotic rabbit aorta. Segments of aorta were pulse-labelled in vitro with [9,10-3H]oleic acid and [1-14C]linoleic acid for 24 h. The incubation medium was replaced with non-radioactive medium and the removal of the endogenously labelled phospholipid, triglyceride and cholesterol ester was followed for a further period of 10 days. Fatty acids incorporated into phospholipid and triglyceride were removed rapidly from the aortic intima, with fractional half-times of 4--5 days. Cholesterol ester fatty acids were removed more slowly from the aortic intima with fractional half-times of 9--12 days. When the removal rate of oleic acid incorporated into phospholipid, triglyceride and cholesterol ester was compared with that of linoleic acid incorporated into the same lipid fractions, no difference between removal of the two fatty acids could be detected with respect to any of the 3 lipid fractions.