Heterogeneity in the Turnover Rates of Liver Cholesterol Esters

Sodium acetate labeled with carbon-14 and a recently developed method of cholesterol ester fractionation were used to investigate the rates at which newly synthesized cholesterol is incorporated into various cholesterol esters in rat liver. Results indicate that the incorporation rates are heterogeneous, differing according to the constituent fatty acids, and that these rates do not represent a simple esteriflcation process in equilibrium with a pool of fatty acids. The pertinence of these findings to the regulation of cholesterol metabolism by the rat is considered. (C.H.)