CHANGES OF PHYLLOQUINONE AND MENAQUINONE-4 CONCENTRATIONS IN RAT-LIVER AFTER ORAL, INTRAVENOUS AND INTRAPERITONEAL ADMINISTRATION

To study the metabolism of K Vitamins (VK) in the liver, two types of natural VK, phylloquinone (K-1) and menaquinone-4 (MK-4), were adminis tered to male Wistar rats orally (P.O.), intravenously (I.V.) and intr aperitonealy (I.P.). Blood and a small portion of the liver (and ascit es by I.P.) were collected 8 times up to 72 h (P.O.) or 24 h (I.V. and I.P.). A modified assay procedure followed by high performance liquid chromatography (HPLC) was developed to detect VK from small amounts o f liver tissue. After oral administration of both K-1 and MK-4 (10 mu mol/kg-P.O.), their concentrations in the liver increased from 1 h the n reached a maximum at 6 h (10 nmol/g v.s. 0.35 nmol/g). After intrave nous or intraperitoneal administration of K-1 and MK-4 (0.5 mu mol/kg- I.V. and I.P.), MK-4 concentrations in the liver reached a maximum fas ter than those of K-1 (1.2 nmol/g - 6 h vs. 0.47 nmol/g - 1 h I.P.). M K-4 also increased in the liver from 6 h to 12 h (0.11 nmol/g - 12 h) after oral administration of K-1 (P.O.). These results indicate that K -1 stays in plasma and liver longer than MK-4 and orally administered K-1 might be transformed partially into MK-4 in the liver.