Scavenger receptor B1 (SR-B1) substrates inhibit the selective uptake of high-density-lipoprotein cholesteryl esters by rat parenchymal liver cells

High-density lipoprotein cholesteryl esters (HDL-CE) are selectively taken up by liver parenchymal cells without parallel apolipoprotein uptake, and this selective uptake route forms an important step in reverse cholesterol transport. Recent data from Acton, Rigotti, Landschulz, Xu, Hobbs and Krieger [(1996) Science 271, 518-520] provide evidence that scavenger receptor B (SR-B1) can mediate selective uptake of HDL-CE. In order to identify if selective uptake of HDL-CE by rat liver parenchymal cells can be mediated by a protein with scavenger receptor properties we performed competition experiments in vivo with substrates for scavenger receptors. Addition of either low-density lipoprotein (LDL), acetylated LDL (AcLDL) or oxidized LDL (OxLDL) only marginally (