出版社：American Society for Biochemistry and Molecular Biology
摘要：The effects of cigarette smoking on n-3 essential FA metabolismwere studied in male and female subjects by fitting the concentration-timecurves of the d5-labeled plasma fatty acids (FAs) originatingfrom a dose of d5-18:3n-3 to a compartmental model of n-3 FAmetabolism. For 3 weeks, female (smokers, n = 5; nonsmokers,n = 5) and male (smokers, n = 5; nonsmokers, n = 5) subjectssubsisted on a beef-based diet. Beginning in the third week,subjects received a dose of d5-18:3n-3 ethyl ester (1 g). PlasmaFAs were analyzed using gas chromatography (GC) and GC-massspectrometry, and the kinetic rate parameters were determinedfrom the concentration-time curves for d5-18:3n-3, d5-20:5n-3,d5-22:5n-3, and d5-22:6n-3. Women smokers had a 2-fold greaterpercent of dose in plasma (5.8% vs. 2.9%; P < 0.01) and ahigher fractional rate constant coefficient for formation ofd5-22:6n-3 from d5-22:5n-3 (0.03 h–1 vs. 0.01 h–1;P < 0.01), compared with nonsmokers. Male smokers had elevatedtotal plasma n-3 FAs, more-rapid turnover of 18:3n-3 (13.3 mg/day–1vs. 4.3 mg/day–1; P < 0.001), a disappearance rateof d5-20:5n-3 that was both delayed and slower (0.001 h–1vs. 0.012 h–1; P < 0.05), and a percentage of d5-20:5n-3directed into formation of d5-22:5n-3 (99% vs. 61%; P < 0.03)that was greater compared with nonsmokers. Smoking increasedthe bioavailability of n-3 FAs from plasma, accelerated thefractional synthetic rates, and heightened the percent formationof some long-chain n-3 PUFAs in men and women.Supplementary key words linolenic acid • docosahexaenoic acid • isotope tracer • mass spectrometry • humans • kinetics • controlled diet
Abbreviations: ANCOVA, analysis of covariance; AUC, area under the concentration-time curve; CV, coefficient of variance; NS, nonsmoking subject; S, smoking subject
