Influence of lysophosphatidylcholine on the C-apolipoprotein content of rat and human triglyceride-rich lipoproteins during triglyceride hydrolysis.
Remnants produced from rat chylomicrons in hepatectomized rats or from human chylomicrons by incubation in postheparin plasma contained much less C-apolipoproteins, but more lysophosphatidylcholine than the parent chylomicrons. A phospholipid-triglyceride emulsion absorbed C-apolipoproteins during incubation in serum, yet not in postheparin plasma, which led to lipid-hydrolysis and increased in lysophosphatidylcholine. The fraction d = 1.006-1.019 g/ml of human serum comprised more lysophosphatidylcholine and less C-apolipoproteins than the fraction d less than 1.006 g/ml. Injection of heparin induced hydrolysis with an increase in lysophosphatidylcholine and loss of C-apolipoproteins in both fractions. These inverse changes of lysophosphatidylcholine and C-apolipoproteins during lipid-hydrolysis suggest a causal relationship, which is strongly supported by the induction of loss of C-apolipoproteins from rat chylomicrons and human triglyceride-rich lipoproteins by addition of lysophosphatidylcholine in vitro. Apolipoprotein C-II was more affected than C-III. These results may elucidate a mechanism for the regulation of the termination of the triglyceride hydrolysis and the final hepatic uptake of remnants.
D000818:Animals; D001056:Apolipoproteins C / Q000097:blood*; D002914:Chylomicrons / Q000097:blood; D004655:Emulsions; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D008074:Lipoproteins / Q000097:blood*; D008244:Lysophosphatidylcholines / Q000097:blood* / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013109:Sphingomyelins / Q000494:pharmacology; D014280:Triglycerides / Q000097:blood*
D001056:Apolipoproteins C; D002914:Chylomicrons; D004655:Emulsions; D008074:Lipoproteins; D008244:Lysophosphatidylcholines; D013109:Sphingomyelins; D014280:Triglycerides; D006493:Heparin