K S Jones1, L J C Bluck, L Y Wang, W A Coward. 1. MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK. kerry.jones@mrc-hnr.cam.ac.uk
Abstract
OBJECTIVES: To measure uptake and disposal kinetics and absolute absorption of vitamin K(1) using two stable isotope-labelled forms of vitamin K(1). SUBJECTS: Ten subjects (nine women and one man) aged between 22 and 31 years, with a mean (+/-standard deviation) body mass index of 22.5+/-2.4 kg/m(2). Subjects took capsules containing 3 microg of methyl-(13)C vitamin K(1), three times a day for six days to reach a steady state for plasma vitamin K(1) isotopic enrichment. On day seven, subjects were given an intravenous dose of Konakion MM to measure disposal kinetics and at the same time, a capsule containing 4 microg of ring-D(4) vitamin K(1) to measure absorption. Plasma vitamin K(1) concentration was measured by high-performance liquid chromatography and isotopic composition by gas chromatography mass spectrometry. RESULTS: The disposal kinetics of the intravenous dose of vitamin K(1) were resolved into two exponentials with half-times of 0.22 (+/-0.14) and 2.66 (+/-1.69) h. Absorption of oral, deuterated vitamin K(1) was 13 (+/-9)%. CONCLUSIONS: Two-compartmental kinetic parameters observed in this study are similar to those obtained previously using radioactive tracers, but there may be additional slow-turnover body pools acting as stores of vitamin K(1). The kinetic parameters determined from the intravenous dose allowed determination of the absolute absorption of vitamin K(1) from a bolus oral dose.
OBJECTIVES: To measure uptake and disposal kinetics and absolute absorption of vitamin K(1) using two stable isotope-labelled forms of vitamin K(1). SUBJECTS: Ten subjects (nine women and one man) aged between 22 and 31 years, with a mean (+/-standard deviation) body mass index of 22.5+/-2.4 kg/m(2). Subjects took capsules containing 3 microg of methyl-(13)C vitamin K(1), three times a day for six days to reach a steady state for plasma vitamin K(1) isotopic enrichment. On day seven, subjects were given an intravenous dose of Konakion MM to measure disposal kinetics and at the same time, a capsule containing 4 microg of ring-D(4) vitamin K(1) to measure absorption. Plasma vitamin K(1) concentration was measured by high-performance liquid chromatography and isotopic composition by gas chromatography mass spectrometry. RESULTS: The disposal kinetics of the intravenous dose of vitamin K(1) were resolved into two exponentials with half-times of 0.22 (+/-0.14) and 2.66 (+/-1.69) h. Absorption of oral, deuterated vitamin K(1) was 13 (+/-9)%. CONCLUSIONS: Two-compartmental kinetic parameters observed in this study are similar to those obtained previously using radioactive tracers, but there may be additional slow-turnover body pools acting as stores of vitamin K(1). The kinetic parameters determined from the intravenous dose allowed determination of the absolute absorption of vitamin K(1) from a bolus oral dose.
Authors: Xueyan Fu; James W Peterson; Mona Hdeib; Sarah L Booth; Michael A Grusak; Alice H Lichtenstein; Gregory G Dolnikowski Journal: Anal Chem Date: 2009-07-01 Impact factor: 6.986
Authors: Kerry S Jones; Les J C Bluck; Laura Y Wang; Alison M Stephen; Celia J Prynne; W Andy Coward Journal: Br J Nutr Date: 2009-06-19 Impact factor: 3.718
Authors: Jessie L Ellis; Xueyan Fu; Ala Al Rajabi; Michael A Grusak; Martin J Shearer; Elena N Naumova; Edward Saltzman; Kathryn Barger; Sarah L Booth Journal: J Nutr Date: 2019-01-01 Impact factor: 4.798