Hepatic Scavenger Receptor BI Promotes Rapid Clearance of High Density Lipoprotein Free Cholesterol and Its Transport into Bile

摘要: The clearance of free cholesterol from plasma lipoproteins by tissues is major quantitative importance, but it not known whether this passive or receptor-mediated. Based on our finding that scavenger receptor BI (SR-BI) promotes (FC) exchange between high density lipoprotein (HDL) and cells, we tested SR-BI would effect FC movement in vivo using [14C]FC- [3H]cholesteryl ester (CE)-labeled HDL mice with increased (SR-BI transgenic (Tg)) decreased attenuated (att)) hepatic expression. initial was Tg 72% att 53%, unchanged apoA-I knockout compared wild-type mice. Transfer to non-HDL esterification were minor could explain differences. uptake 34% 22%. CE gave similar results, much slower rates. primary hepatocytes 2.2- 2.6-fold (1-h incubation), respectively, control hepatocytes. In mice, the biliary secretion [14C]FC markedly increased, whereas [3H]FC appeared after a slight delay. Thus, mouse, portion mediated SR-BI.