HEPATOCELLULAR TRANSPORT AND SECRETION OF BILIARY PHOSPHOLIPIDS

Recent progress has begun to elucidate molecular and cellular mechanis ms whereby bile salts stimulate hepatocellular selection, transport, a nd biliary secretion of phospholipids, which are enriched (up to 95%) in phosphatidylcholines. This article first summarizes classical obser vations concerning the molecular structures of biliary phospholipids, as well as the role of bile salts in promoting their secretion into bi le. New data are then reviewed and synthesized into a working model fo r biliary phospholipid secretion. An important feature is that this mo del is selective for biliary phospholipids and necessitates a largely independent pathway for cholesterol secretion into bile.