부산대학교 도서관

Objectives:To measure uptake and disposal kinetics and absolute absorption of vitamin K1 using two stable isotope-labelled forms of vitamin K1.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/m2. Subjects took capsules containing 3 μg of methyl-13C vitamin K1, three times a day for six days to reach a steady state for plasma vitamin K1 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 μg of ring-D4 vitamin K1 to measure absorption. Plasma vitamin K1 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 K1 were resolved into two exponentials with half-times of 0.22 (±0.14) and 2.66 (±1.69) h. Absorption of oral, deuterated vitamin K1 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 K1. The kinetic parameters determined from the intravenous dose allowed determination of the absolute absorption of vitamin K1 from a bolus oral dose.European Journal of Clinical Nutrition (2008) 62, 1273–1281; doi:10.1038/sj.ejcn.1602859; published online 1 August 2007 [ABSTRACT FROM AUTHOR]