title: In vivo determination of very-low-density lipoprotein-apolipoprotein B100 secretion rates in humans with a low dose of l-[1-13C]valine and isotope ratio mass spectrometry.
abstract: The aim of the present study was to determine the rate of very-low-density lipoprotein (VLDL)-apolipoprotein (apo) B100 secretion in humans with a minimized amount of l-[1-13C]valine infusion in combination with the use of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis. To compare this method with the conventional gas chromatography/mass spectrometry (GC/MS) technique, two different dosages of l-[1-13C]valine and both analytical techniques were compared in a single study. A priming dose of l-[1-13C]valine (2 micromol/kg) followed by a constant infusion (2 micromol/kg/h) was given for 3 h, directly followed by a second priming dose (15 micromol/kg) and a constant infusion (15 micromol/kg/h) for 4 h. The fractional secretion rate obtained by GC/C/IRMS measurements from the first 3 h of infusion (mean +/- SD: 0.22 +/- 0.09 pools/h) was similar to that obtained by GC/MS during the last 4 h of infusion (0. 23 +/- 0.07 pools/h; P = 0.56). In conclusion, superior analytical accuracy and sensitivity of GC/C/IRMS enable measurements of VLDL-apo B100 secretion with much lower doses of l-[1-13C]valine and allow for reduction of experimental costs.
authors.affiliation: Department of Nephrology and Hypertension, University Hospital Utrecht, The Netherlands.
authors.forename: M G
authors.initials: MG
authors.lastname: de Sain-van der Velden
authors.forename: T J
authors.initials: TJ
authors.lastname: Rabelink
authors.forename: M M
authors.initials: MM
authors.lastname: Gadellaa
authors.forename: H
authors.initials: H
authors.lastname: Elzinga
authors.forename: D J
authors.initials: DJ
authors.lastname: Reijngoud
authors.forename: F
authors.initials: F
authors.lastname: Kuipers
authors.forename: F
authors.initials: F
authors.lastname: Stellaard
mesh_terms: D053299:Apolipoprotein B-100; D001055:Apolipoproteins B / Q000097:blood* / Q000378:metabolism; D002247:Carbon Isotopes; D006801:Humans; D008079:Lipoproteins, VLDL / Q000097:blood* / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods*; D014633:Valine / Q000737:chemistry*
chemical_list: D053299:Apolipoprotein B-100; D001055:Apolipoproteins B; D002247:Carbon Isotopes; D008079:Lipoproteins, VLDL; D014633:Valine