PROBABLE SOURCES OF PLASMA CHOLESTEROL DURING PHOSPHATIDE INDUCED HYPERCHOLESTEROLEMIA

Rats in isotopic steady state with respect to 4-14C-cholesterol were infused intravenously with massive amounts of lecithin and also injected once with Na acetate3H. During the following 8 hr their plasma gained an average of 11.3 mg of cholesterol; the specific activity of14C-cholesterol fell in plasma while total14C-cholesterol and3H activity doubled as compared to controls. The specific activity of14C-cholesterol diminished in livers of rats receiving lecithin but not in controls. Specific activity of either isotope in cholesterol of intestine, lungs, muscle, skin and brains was the same in control and experimental groups. Total activity of14C and3H fell in cholesterol of liver. The results show that plasma accumulation of cholesterol during lecithin infusion derives from both cholesterol pre-existing prior to infusion and from that newly synthesized after the start of infusion and that about one third of this cholesterol of mixed origin is supplied from the liver. The authors speculatively suggest skin as a likely source for most of the remainder, with a small additional contribution from brain. © 1969 American Oil Chemists' Society.