Alterations of HDL cholesterol distribution induced by incubation of human serum.
The study of high density lipoprotein (HDL) alterations induced by serum incubation was undertaken by a new approach. Subfractions of HDL were separated by gradient gel electrophoresis, without preliminary ultracentrifugation, and were characterized by their size range. After dissolution of the polyacrylamide gel, each subfraction was analyzed for its total- and unesterified-cholesterol content by gas chromatography. We have observed that a general displacement of HDL cholesterol towards the subspecies of high size range occurred during serum incubation at 37 degrees C, contemporaneously with cholesterol esterification. This displacement could not be identified with a HDL3 to HDL2 conversion since it occurred within HDL3 and HDL2. It is probably the indication of a complex HDL conversion leading to particles of increased sizes. HDL alterations occurring upon serum incubation appear to be the consequence of the activity of an HDL conversion factor, which is thermolabile, non-dialysable, present in the d greater than 1.25 serum fraction and differs from lecithin:cholesterol acyltransferase and cholesteryl ester transfer protein. They could be considered as preliminary enzymatic transformations, necessary for the action of lecithin:cholesterol acyltransferase and as the first step of a metabolic sequence including, successively, HDL conversion, cholesterol esterification by lecithin:cholesterol acyltransferase and cholesteryl ester transfer.
D000328:Adult; D000818:Animals; D001769:Blood; D002784:Cholesterol / Q000097:blood*; D002788:Cholesterol Esters / Q000097:blood; D008076:Cholesterol, HDL; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008074:Lipoproteins / Q000097:blood; D008075:Lipoproteins, HDL / Q000097:blood*; D053439:Lipoproteins, HDL2; D053440:Lipoproteins, HDL3; D008297:Male; D008875:Middle Aged; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity
D002788:Cholesterol Esters; D008076:Cholesterol, HDL; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D053439:Lipoproteins, HDL2; D053440:Lipoproteins, HDL3; D002784:Cholesterol