Uptake and metabolism of 3H-fatty acid labelled lecithin by normal and atherosclerotic intima in vivo and in vitro

Following the intravenous injection of tracer doses of 3H-fatty acid labelled lecithin into normally fed rabbits, minimal incorporation into serum cholesterol ester over a 6-hour period was observed. The labelled phospholipid was rapidly removed from the serum primarily by R.E. tissues with little uptake by the aorta. The uptake and metabolism of 3H-fatty acid labelled lecithin by explants of normal and cholesterol-fed rabbit aortas was also investigated in vitro for periods up to 8 days. Low uptake and incorporation into cholesterol ester was observed for the normal aortic explants. The labelled phospholipid was taken up to a greater extent by explants from cholesterol-fed rabbit aortas and the fatty acid incorporated into both triglyceride and cholesterol ester in the explants. The incorporation of fatty acid into cholesterol ester from phospholipid was associated with hydrolysis of the phospholipid and re-incorporation of the fatty acid into cholesterol ester, rather than by the action of lecithin cholesterol acyl transferase.