title: Quantitative studies of lipoprotein-X in familial lecithin: cholesterol acyltransferase deficiency and during cholesterol esterification.
abstract: In eight patients with familial lecithin: cholesterol acyltransferase (LCAT) deficiency the plasma concentration of the abnormal lipoprotein LP-X ranged from 43 mg/100 ml to 251 mg/100 ml with a mean of 127 mg/100 ml. This is above the mean level of LP-X found in a group of patients with intrahepatic cholestasis (49 mg/100 ml) and below the mean level found in patients with extrahepatic cholestasis (341 mg/100 ml). Following blood transfusions, an increase in LCAT activity and a decrease in the plasma concentration of LP-X were observed. This decrease was not a simple dilution phenomenon. Quantitation of LP-X during long-term incubation of a whole plasma system demonstrated that LP-X was a source of free cholesterol (FC) in the LCAT reaction. More free cholesterol was derived from LP-X during cholesterol esterification than corresponding to the percentage of the plasma free cholesterol found in the LP-X fraction. The present investigation did not answer the question whether LP-X only was an easily accessible source of free cholesterol for cholesterol esterification or whether LP-X acted directly as a substrate for the LCAT reaction.
mesh_terms: D000217:Acyltransferases / Q000097:blood* / Q000172:deficiency; D000328:Adult; D001803:Blood Transfusion; D002784:Cholesterol / Q000378:metabolism*; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000201:enzymology* / Q000235:genetics*; D016030:Kidney Transplantation; D008074:Lipoproteins / Q000097:blood*; D008103:Liver Cirrhosis / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010713:Phosphatidylcholines
chemical_list: D008074:Lipoproteins; D010713:Phosphatidylcholines; D002784:Cholesterol; D000217:Acyltransferases