title: In vivo distribution and turnover of trans- and cis-10-octadecenoic acid isomers in human plasma lipids.
abstract: Triacylglycerols containing deuterium-labeled trans-10- and cis-10-octadecenoic acid (10t-18:1, 10c-18:1) plus the triacylglycerol of deuterated cis-9-octadecenoic acid (9c-18:1) were fed as a mixture to two young, adult male subjects. Analysis by mass spectroscopy of the labeled fats in blood samples collected periodically for 48 h allowed the uptake, distribution and turnover of both 10-octadecenoic acid isomers to be directly compared to 9c-18:1. A feature of this study is that actual weight data for the labeled fats were obtained. These data allowed plasma triacylglycerol turnover rates of 3.47-5.13 mg/min per kg to be estimated. Plasma and chylomicron triacylglycerol data also provided evidence that absorption of the deuterated fats mobilized 10-12 g of a triacylglycerol pool present in the intestinal cells. Other results are summarized as follows: the 10t-, 10c- and 9c-18:1 fatty acids were equally well absorbed, both delta 10-18:1 isomers were oxidized more rapidly than 9c-18:1, conversion of the delta 10-18:1 isomers into their corresponding 16:1 isomers was about 3-times faster than for 9c-18:1, the delta 10-18:1 isomers were preferentially incorporated at the 1-acyl and excluded from the 2-acyl position of phosphatidylcholine, esterification of cholesterol with the delta 10-18:1 fatty acids was 2.5-4.3-times slower than for 9c-18:1 and desaturation and elongation rates for the delta 10-18:1 acids were very low.
mesh_terms: D000328:Adult; D002788:Cholesterol Esters / Q000097:blood; D003903:Deuterium; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006801:Humans; D007408:Intestinal Absorption; D007536:Isomerism; D008055:Lipids / Q000097:blood*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D009829:Oleic Acids / Q000097:blood*; D010743:Phospholipids / Q000097:blood; D013237:Stereoisomerism; D014280:Triglycerides / Q000097:blood
chemical_list: D002788:Cholesterol Esters; D005230:Fatty Acids, Nonesterified; D008055:Lipids; D008074:Lipoproteins; D009829:Oleic Acids; D010743:Phospholipids; D014280:Triglycerides; D003903:Deuterium; C046568:10-octadecenoic acid