Hepatocellular transport and secretion of biliary phospholipids

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