Effect of the phospholipid vehicle on the transport of cholesterol in rats.

Rats were injected intravenously with liposomes made of [4(-14)C] cholesterol with [32P]lysolecithin, or [4(-14)C]cholesterol with [32P]lecithin. The clearance of both radioactive labels from plasma was observed, as well as their distribution in the organs after 15 and 60 min. At the same time, the esterification of injected [14C]cholesterol and the conversion of [32P]lysolecithin to [32P]lecithin and vice versa were examined. [14C]Cholesterol administered with lysolecithin was cleared from the plasma at a higher rate than with lecithin. Consequently the radioactivity of [14C]cholesterol in the aorta, heart, lung, kidney and liver changed with the applied phospholipid; with lysolecithin it was higher than with lecithin. Lysolecithin itself was distributed among the organs more evenly than lecithin, which accumulated most in the liver. If administered with lysolecithin, [14C]cholesterol was esterified in the plasma in a significantly higher proportion than if administered with lecithin. The antiatherogenous effect of lecithin and the atherogenous effect of lysolecithin are considered on the basis of different transport properties of these phospholipids.