Comparison of very-low-density lipoproteins isolated from rat liver perfusate, rat serum and human plasma as acceptors for cholesteryl ester transfer.

Using two methods, we have compared the ability of three types of very-low-density lipoprotein (VLDL), namely, rat hepatic perfusate VLDL, rat serum VLDL and human plasma VLDL, to accept cholesteryl esters from human plasma high-density lipoprotein (HDL). Both net mass and isotopic transfers of cholesteryl ester were evaluated. The VLDL concentration in the incubation media was adjusted on the basis of equivalent amounts of either cholesteryl ester, apolipoprotein B or triacylglycerol. In each case, the net mass transfer of cholesteryl ester was found to be greatest to rat hepatic VLDL, lower to rat serum VLDL and lowest to human plasma VLDL. Similar results were obtained with the isotopic transfer method when the VLDL concentration was adjusted on the basis of cholesteryl ester or apolipoprotein B. However, when VLDL were matched on the basis of triacylglycerol concentration, the isotopic transfer rate into human plasma VLDL was twice as high as into rat hepatic VLDL which presumably reflects the decreased number of hepatic VLDL particles by this criterion. In conclusion under fasted conditions (chylomicron excluded), nascent VLDL have been shown to be the best cholesteryl ester acceptor compared to their plasma counterpart.