Comparative Metabolism of Phylloquinone and Menaquinone-9 in Rat Liver

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Abstract
The hepatic turnover of phylloquinone and menaquinone-9 (MK-9) and their relative efficacy in satisfying the dietary requirement for vitamin K were compared in male rats. Rats fed 1.1 µmol phylloquinone/kg diet had higher initial liver and serum vitamin K concentrations than rats fed an equimolar amount of MK-9. The initial rate of hepatic turnover of phylloquinone was two to three times as rapid as that of MK-9. After about 48 h of vitamin K restriction there were no significant differences in hepatic vitamin K concentration of rats fed phylloquinone or MK-9. Phylloquinone was much more effective than MK-9 in maintaining normal vitamin K status at low dietary concentrations (0.2 µmol/kg diet), whereas at high dietary concentrations (5.6 µmol/kg diet) they were equally effective.