Hepatic lipid secretion and cholelithiasis

Recent work has suggested that secretion of lithogenic hepatic bile is a major factor in the etiology, and a prerequisite abnormality to the growth and maturation of cholesterol gallstones. Cholesterol is normally solubilized in bile by mixed micelles of bile acids and lecithin. A decreased bile acid pool or a decrease in the ratio of bile acid and lecithin to cholesterol characterizes lithogenic bile. These observations have stimulated investigation of biliary lipid secretion, relevant to pursuing the genesis of the alterations. This review summarizes current knowledge of the individual and interrelated biosynthesis, kinetics, biliary secretion, and regulation of cholesterol, bile acid and lecithin. Investigations of induced alterations by drugs, hormones and diet are also reviewed. The lithogenic potential of bile can be decreased by chenodeoxycholic acid, but more work is needed, in particular, to define the hepatic enzymatic abnormality that causes the secretion of lithogenic bile.