title: Incorporation of deuterium-labeled trans- and cis-13-octadecenoic acids in human plasma lipids.
abstract: The absorption and distribution of deuterated trans- and cis-13-octadecenoic acid (13t-18:1 and 13c-18:1) in plasma lipids were compared to deuterated cis-9-octadecenoic acid (9c-18:1) in two young adult male subjects. A mixture of triglycerides was fed in a multiple-labeled experiment where each triglyceride contained a fatty acid labeled with a different number of deuterium atoms. Analysis of human plasma lipids by mass spectroscopy allowed the distribution of the two 13-octadecenoic acid isomers to be directly compared to cis-9-octadecenoic acid. Plasma lipids selectively excluded both the 13t-18:1 and 13c-18:1 isomers relative to 9c-18:1 in all neutral and phospholipid fractions. Discrimination against incorporation of the 13t-18:1 isomer into plasma cholesteryl ester and 2-acyl phosphatidylcholine was nearly absolute. The 1-acyl phosphatidylcholine fraction exhibited a large positive selectivity for the 13t-18:1 isomer. Differences in the relative distribution of the trans and cis 13-18:1 isomers vs. 9c-18:1 in the various lipoprotein lipid classes were found. Analysis of the chylomicron triglyceride component of the plasma lipids indicated all three fatty acids were equally well absorbed.
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000378:metabolism; D002788:Cholesterol Esters / Q000097:blood; D003903:Deuterium; D004912:Erythrocytes / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007536:Isomerism; D007700:Kinetics; D008055:Lipids / Q000097:blood*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D009829:Oleic Acids / Q000097:blood*; D010743:Phospholipids / Q000097:blood; D014280:Triglycerides / Q000097:blood
chemical_list: D002788:Cholesterol Esters; D008055:Lipids; D008074:Lipoproteins; D009829:Oleic Acids; D010743:Phospholipids; D014280:Triglycerides; C037352:13-octadecenoic acid; D003903:Deuterium