Sodium oleate dissociates the heteroexchange of cholesteryl esters and triacylglycerol between HDL and triacylglycerol-rich lipoproteins.

Mixtures of human high-density lipoproteins (HDL) and triacylglycerol-rich lipoproteins (TGRL) have been incubated in the presence of partially pure cholesteryl ester transfer protein (CETP). There were net mass transfers of cholesteryl ester from HDL to TGRL and of triacylglycerol from TGRL to HDL which were accompanied by the formation of minor subpopulations of small HDL particles. When the mixture of HDL, TGRL and CETP was supplemented with fatty acid-poor bovine serum albumin (40 mg/ml) there was a 7% reduction in the transfer of cholesteryl esters out of HDL (P less than 0.05) and a 14% increase in the transfer of triacylglycerol into HDL (P less than 0.05); there was also a reduction in the formation of very small HDL particles. In contrast, when the mixture of HDL, TGRL and CETP was supplemented with 0.16 mM sodium oleate the transfer of cholesteryl esters out of HDL was increased by 31% (P less than 0.001) and the transfer of triacylglycerol into HDL was decreased by 25% (P less than 0.01); under these conditions the formation of very small HDL particles was enhanced. It has been concluded that in the presence of sodium oleate, there is a dissociation of the CETP-mediated heteroexchange of cholesteryl esters and triacylglycerol between HDL and TGRL.