QUANTITATIVE KINETIC EVALUATION OF PRECURSOR SOURCES AND TURNOVER OF HIGH DENSITY LIPOPROTEIN CHOLESTEROL ESTERS

A B S T R A C T The purpose of this study is to delineate the immediate sources and fractional turnover of high density lipoprotein (HDL) esterified cholesterol in man. Various labeled preparations were administered in 11 experiments to six subjects who had either a complete bile fistula (maximally stimulated cholesterol metabolism) or an intact enterohepatic circulation. The administered tracers included [3H]mevalonic acid; [14C]cholesterol bound to albumin; low density lipoprotein (LDL) free [3H] or ['4C]cholesterol; HDL free [3H] or [14C]cholesterol; HDL esterified [3H]cholesterol; and LDL esterified [3H1]cholesterol. Blood samples were obtained at frequent intervals for up to 5 d after the administration of tracers. The mass and radioactivity in individual plasma lipoprotein (very low density lipoprotein [VLDL], HDL, and LDL) free and esterified cholesterol were determined. The data were subjected to multicompartmental analysis using the SAAM-27 computer program. The