Plasma concentration of lipoprotein-X (LP-X) in experimental bile duct obstruction.

Sequential quantitative determinations of lipoprotein-X (LP-X), measurements of plasma lipids, initial rate of cholesterol esterification, and liver function tests were performed after experimental cholestasis in 6 dogs. In 3 animals ligation and transsection of the common bile duct were combined with cholecystectomy. In 2 other dogs a similar operation, but without removal of the gallbladder, was carried out. In the bile-duct-obstructed and cholecystectomized dogs, LP-X appeared 11-21 hours after operation, and in dogs with preserved gallbladder 32 hours after operation. During the observation periods (6-41 days), the LP-X levels were much higher in the cholecystectomized dogs than in the ones with preserved gallbladders. In most of the bile-duct-obstructed dogs the curves of LP-X concentrations in plasma were bi-phasic. The first peak after 1 to 5 days was followed by a fall, and 10 to 14 days after operation another rise was observed. Concomitant with the changes in the level of LP-X, fluctuations in the levels of phospholipids and free cholesterol occurred. An inverse relationship between LP-X and the activity of lechithin: cholesterol acyltransferase was found.