Chylomicron Metabolism: Alterations of Absorbed Labeled Lipid

Abstract

Palmitic acid-1-C14 in olive oil was fed to rats, and after absorptive periods of 1 1/2, 4 and 5 hours the animals were exsanguinated. Chylomicron-free plasma or blood diluted with urea solution was prepared by high speed centrifugation. Radioactive assay of the plasma or diluted blood before and after centrifugation indicates that an increasing percentage of the total radioactivity no longer resides in the chylomicrons. When particulate-free plasma was subjected to trichloroacetic acid precipitation, between 71 and 95% of the radioactivity was in the precipitate. Attempts to extract the lipids from the precipitate demonstrated that only a portion of the radioactivity resided in the lipid fraction. The relationships of these observations to the current concepts of lipid transport are discussed.