Mechanism of Secretion of Biliary Lipids

Presented in part at the American Gastroenterological Association Meeting, San Francisco, California, May, 1974, and in part at the Bile Acid Meeting (III), Freiburg, Germany, June, 1974. Received for publication 8 April 1974 and in revised form 9 September 1974. lecithin. These data provide evidence that (a) biliary lecithin and cholesterol are derived from a microsomal subpool regulated by the flux of enterohepatic bile acids, (b) the role of the bile canalicular membranes with respect to biliary lipids is primarily transport rather than synthesis, and (c) lecithin and cholesterol are transported together from microsomes to bile. The findings are consistent with the existence of a cytoplasmic lipid complex within the hepatocyte which is actively involved in the intermembrane transport of biliary lipid.