出版社：American Society for Biochemistry and Molecular Biology
摘要：We quantified incorporation rates of plasma-derived -linolenicacid (-LNA, 18:3n-3) into "stable" liver lipids and the conversionrate of -LNA to docosahexaenoic acid (DHA, 22:6n-3) in malerats fed, after weaning, an n-3 PUFA-adequate diet (4.6% -LNA,no DHA) or an n-3 PUFA-deficient diet (0.2% -LNA, no DHA) for15 weeks. Unanesthetized rats were infused intravenously with[1-14C]-LNA, and arterial plasma was sampled until the liverwas microwaved at 5 min. Unlabeled -LNA and DHA concentrationsin arterial plasma and liver were reduced >90% by deprivation,whereas unlabeled arachidonic acid (20:4n-6) and docosapentaenoicacid (22:5n-6) concentrations were increased. Deprivation didnot change -LNA incorporation coefficients into stable liverlipids but increased synthesis-incorporation coefficients ofDHA from -LNA by 6.6-, 8.4-, and 2.3-fold in triacylglycerol,phospholipid, and cholesteryl ester, repectively. Assuming thatsynthesized-incorporated DHA even tually would be secreted withinlipoproteins, calculated liver DHA secretion rates equaled 2.19and 0.82 µmol/day in the n-3 PUFA-adequate and -deprivedrats, respectively. These rates exceed the published rates ofbrain DHA consumption by 6- and 10-fold, respectively, and shouldbe sufficient to maintain normal and reduced brain DHA concentrations,respectively, in the two dietary conditions.Supplementary key words deprivation • incorporation • turnover • synthesis • pulse labeling • diet • brain • polyunsaturated fatty acid
Abbreviations: AA, arachidonic acid (20:4n-6); DHA, docosahexaenoic acid (22:6n-3); DPA, docosapentaenoic acid (22:5); EPA, eicosapentaenoic acid (20:5n-3); FAME, fatty acid methyl ester; LA, linoleic acid (18:2n-6); -LNA, -linolenic acid (18:3n-3); UV, ultraviolet
-linolenic acid (
