ABSTRACT
Cholesterol feeding induced a marked hypercholesterolemia with a significant change in the chemical composition of different lipid and lipoprotein fractions. The change of lipoprotein composition in the prairie dog resembles that of human hyper-beta-lipoproteinemia. It is assumed that the mechanism of gallstone formation in humans is not identical to that of the prairie dog. The absolute increase in the hepatic free cholesterol in the prairie dog is due to the dietary cholesterol while the relative increase in free cholesterol in humans is due to a high FC/EC which is probably due to a defect in cholesterol esterification or cholesterol ester hydrolyzing activity.
Subject(s)
Cholesterol, Dietary/metabolism , Diet, Atherogenic , Lipids/blood , Lipoproteins/blood , Sciuridae/blood , Animals , Disease Models, Animal , Fatty Acids/blood , Liver/metabolism , Male , Sterol O-Acyltransferase/metabolismABSTRACT
Liver biopsy and serum specimens obtained from patients with cholesterol gallstones and from a control group were analysed for their different lipids and lipoprotein fractions. The ratio of free cholesterol to esterified cholesterol (CF/CE) was significantly (P less than 0.001) higher in the livers of gallstone-forming patients. There was no significant difference in the levels of total lipids, total cholesterol, phospholipids and glycerides. Beta-lipoprotein fraction (LDL) was higher in gallstone-forming patients. It is concluded that the decrease in esterified cholesterol of gallstone-formers may provide an important clue to an understanding of the physiology and chemistry of stone-formation in humans.
Subject(s)
Cholelithiasis/metabolism , Lipid Metabolism , Liver/metabolism , Cholesterol/metabolism , Cholesterol Esters/metabolism , Fatty Acids/metabolism , Glycerides/metabolism , Humans , Lipids/blood , Lipoproteins, LDL/metabolism , Phospholipids/metabolismABSTRACT
Bile acid secretion was studied in isolated rat hepatocytes cultured in medium supplemented with cofactors and succinate. Succinate as a respiratory substrate was found to be essential for bile acid synthesis. Feedback mechanism was demonstrated with different inhibitory potency of different bile acids on bile acid synthesis in isolated hepatocytes.
