Incorporation of dietary n-3 fatty acids into molecular species of phosphatidyl choline and cholesteryl ester in normal human plasma.
To understand the differences in the antiatherogenic actions of eicosapentaenoic acid (EPA, 20:5) and docosahexaenoic acid (DHA, 22:6), we determined their incorporation into molecular species of phosphatidylcholine (PC) and cholesteryl ester (CE) after feeding 12 g marine lipid concentrate/d to six normolipidemic males for 28 d. The time course of incorporation of EPA into plasma PC and CE showed a precursor-product relationship. In contrast, the DHA concentration of CE was markedly lower than that in PC, and the EPA-DHA ratio was 2-6-fold higher in CE than in PC at all time intervals. Three PC species--16:0-20:5, 16:0-22:6, and 18:0-20:5--increased, whereas 18:1-18:2, 18:0-18:2, and 16:0-20:3 decreased. In vitro formation of CE species in plasma by lecithin-cholesterol acyltransferase (LCAT) showed an increased formation of 20:5 CE but not 22:6 CE, indicating that DHA is a poor substrate for LCAT. These results demonstrate a differential incorporation of EPA and DHA into plasma lipids, which may be related to the differences in their biological effects.
Subbaiah
P V
PV
Department of Medicine, Rush Medical College, Chicago, IL.
Kaufman
D
D
Bagdade
J D
JD
D000328:Adult; D002788:Cholesterol Esters / Q000097:blood*; D004281:Docosahexaenoic Acids / Q000097:blood; D015118:Eicosapentaenoic Acid / Q000097:blood; D005227:Fatty Acids / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D010713:Phosphatidylcholines / Q000097:blood* / Q000737:chemistry; D012016:Reference Values; D013997:Time Factors
D002788:Cholesterol Esters; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D008055:Lipids; D010713:Phosphatidylcholines; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid