title: Isotope ratio mass spectrometry, compared with conventional mass spectrometry in kinetic studies at low and high enrichment levels: application to lipoprotein kinetics.
abstract: The aim of the present study was to compare the performances of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) in stable isotope kinetic studies. In the analysis of cholesterol and leucine, GC/C/IRMS gave precise and linear results over a large scale of 13C enrichment (-22 to +760 delta/1000 for cholesterol, -26 to +600 delta/1000 for leucine). Compared with GC/MS, GC/C/IRMS was much more accurate and reproducible, especially at low [13C]-cholesterol enrichment (-12 delta/1000), with cholesterol samples ranging from 0.11 to 17 ng. Cholesterol ester kinetics in rabbit plasma low-density lipoproteins was studied after injection of 3 mg [3,4-(13)C]cholesterol. A smooth and regular kinetic curve was obtained with GC/C/IRMS; results were much less reproducible with GC/MS. Finally, the performances of GC/C/IRMS were demonstrated in the simultaneous kinetic study of three human plasma apolipoproteins during a primed constant infusion of 0.7 mg.kg-1.h-1 L-[l-13C]leucine. Kinetic curves were obtained in very-low-density lipoproteins and low-density lipoproteins for apolipoprotein B100, and in high-density lipoproteins for apolipoproteins AI and AIL.
authors.affiliation: Laboratoire de Biochimie des Lipoprotéines, INSERM CJF 93-10, Faculté de Médecine, Dijon, France.
authors.forename: F
authors.initials: F
authors.lastname: Pont
authors.forename: L
authors.initials: L
authors.lastname: Duvillard
authors.forename: C
authors.initials: C
authors.lastname: Maugeais
authors.forename: A
authors.initials: A
authors.lastname: Athias
authors.forename: L
authors.initials: L
authors.lastname: Perségol
authors.forename: P
authors.initials: P
authors.lastname: Gambert
authors.forename: B
authors.initials: B
authors.lastname: Vergès
mesh_terms: D000328:Adult; D000818:Animals; D001053:Apolipoproteins / Q000097:blood; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D002247:Carbon Isotopes; D002784:Cholesterol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D008078:Cholesterol, LDL / Q000097:blood; D005069:Evaluation Studies as Topic; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D006801:Humans; D007700:Kinetics; D007930:Leucine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D008074:Lipoproteins / Q000097:blood*; D011817:Rabbits; D012015:Reference Standards
chemical_list: D001053:Apolipoproteins; D002247:Carbon Isotopes; D008078:Cholesterol, LDL; D008074:Lipoproteins; D002784:Cholesterol; D007930:Leucine