Changes in biliary lipid concentrations in bile duct obstruction: an experimental study.

Changes in biliary concentrations of bile acids, phospholipids and cholesterol and biliary pressures were measured in dogs. These parameters were studied during 7-day periods of partial biliary obstruction, of varying degrees, and after 24-hour and 48-hour periods of complete obstruction. The sample were obtained via an exteriorized but intact enterohepatic circulation allowing the introduction of varying degrees of obstruction and bile sampling. Biliary obstruction reduced the concentration of all biliary lipids especially when the obstruction produced pressures in excess of 75% of the maximum biliary secretion pressure. Only immediately after the release of a 48-hour period of complete obstruction did the risk of cholesterol supersaturation of bile occur. However, at that time there was a greatly reduced concentration of lipids in the bile and the amount of cholesterol that could potentially have precipitated was very small. It is suggested that this supersaturation would not play a significant role in the formation of gallstones.