Plasma lipoprotein changes in experimental cholestasis in the dog

Abstract

Plasma lipoproteins were compared before and after surgical induction of extrahepatic biliary obstruction in dogs by immunochemical techniques, zonal ultracentrifugation and gel filtration. A considerable increase in LDL was found one week after operation, with a zonal ultracentrifugal pattern which was more complex than that found before operation. The lipid composition was characterized by an increase of phospholipids and a decrease of triglycerides in cholestatic LDL fractions. None of the fractions displayed the inverse cholesterol-cholesterol ester ratio, characteristic for human LP-X. The apoprotein composition of cholestatic LDL was also markedly changed. Apoprotein A I, already present in the normal LDL2 subclass, increased and two apoproteins with apparent molecular weight of 35000-40000 appeared in considerable amounts. The amount of HDL was decreased during cholestasis without any appreciable changes in composition.