LIPID METABOLISM IN THE DEVELOPMENT OF CHOLESTEROL GALLSTONES IN HAMSTERS : IV . THE EFFECT OF ESSENTIAL PHOSPHOLIPIDS AND PLANT STEROLS ON THE BILIARY LIPIDS

Female golden hamsters were fed either with a lithogenic diet alone (72.3% glucose diet according to Dam's prescription) or in combination with 0.7 ml/2days of 5 g/dl essential phospholipids (EPL) or 2.9 % plant sterols for 30 days.

Hamsters fed with the lithogenic diet were found to have produced a high level of cholesterol (lithogenic) in bile as well as formation of gallstone in the gallbladder.

Analysis of the bile lipids proved that EPL very slightly (NS) and plant sterols significantly lowered the lithogenic index of bile preventing gallstone formation. EPL increased not only biliary phospholipid but also cholesterol and total bile acid concentrations. But the increased total bile acids seemed to be due to the increased deoxycholic acid contaminated in an EPL solution as a detergent. Fatty acid analysis of biliary phospholipids revealed that the increased phospholipids contained a large amount of C 18 : 2 and C 18 : 3.

The administration of plant sterols decreased not only biliary cholesterol but also phospholipids accompanied by alteration of their fatty acid composition. It also decreased chenodeoxycholic and its secondary bile acid (lithocholic acid) concentrations diminishing their pool sizes.

However, the administration of plant sterols did not alter the glycine/taurine ratio which is often elevated in various hepatobiliary diseases.

EPL and plant sterols improve lithogenic bile and prevent gallstone formation not only by affecting biliary cholesterol, phospholipid and bile acid concentrations but also by altering the fatty acid composition of phospholipids and some of bile acid concentration and their pool sizes.