Chylomicron metabolism in rabbits fed diets with or without added cholesterol

Intestinal lymph chylomicrons, isotopically labelled with radioactive triacylglycerol and cholesterol, were injected into normally fed and cholesterol-fed rabbits in order to establish the pattern of clearance of intestinal lipoproteins from the plasma. In normal rabbits the cholesterol moiety of chylomicrons was removed from the plasma less readily than triacylglycerol. In cholesterol-fed rabbits, the clearance of triacylglycerol was unaltered, but clearance of chylomicron cholesterol was further retarded. The majority of the injected lymph cholesterol was recovered in d less than 1.019 g/ml lipoproteins. These observations support the notions that clearance of chylomicron remnants is impaired in the rabbit, and that hypercholesterolaemia in the cholesterol-fed rabbit is due to an accumulation of chylomicron remnants in the plasma.