ABSTRACT
The initial fractional and molar rates of lecithin:cholesterol acyltransfer and the plasma concentrations of unesterified and esterified cholesterol, total phospholipids, triacylglycerol, high density lipoprotein-cholesterol and aplipoprotein B-linked cholesterol were determined for young healthy women and for groups of female pigs, rabbits, rats and cattle. Coefficients were calculated for the simple and partial correlations between acyltransfer rates and lipid and lipoprotein concentrations. In all species molar acyltransfer rates were significantly corrlated with unesterified cholesterol levels. For women, pigs and rabbits (atherosclerosis-susceptible species) acyltransfer rate was significantly correlated with triacylglycerol and apolipoprotein B-linked cholesterol levels, but not with high desnity lipoprotein-cholesterol. In contrast, acyltransfer rates for rats and bovines (atherosclerosis-resistant species) were significantly correlated with high density lipoprotein-cholesterol, but not with the other parameters. These results, together with the corresponding partial correlation analyses, suggest significant functional differences for lecithin:cholesterol acyltransfer in atherosclerosis-resistant and athrosclerosis-susceptible species and that in the latter group, this enzyme may be mainly invilved in the disposal of cholesterol from triacylglycerol-rich lipo-proteins rather than in removing excess tissue cholesterol for transport to the liver