Intestinal, hepatic, and circulating vitamin Klev#D#D#D levels at low and hight intakes of vitamin K in rats
2000
Koivu-Tikkanen, T.J. | Schurgers, L.J. | Thijssen, H.H.W. | Vermeer, C.
The aim of the present study was to assess how high doses of dietary vitamin K influence the intestinal profile of K-vitamins in vitamin K-deficient rats, and whether the induced changes are reflected in the hepatic vitamin K store. Vitamin K-deficient rats were fed for 10d on diets containing different forms of vitamin K, and it was determined how these diets affected the vitamin K concentration at various sites of the intestine, serum, and the liver. It was found that the absorption of phylloquinone from standard food is not more than 10%, while the absorption of pharmacological doses of oil-solubilized phylloquinone and menaquinone-4 was also far from complete (18 and 55% respectively). High intakes of phylloquinone suppress the colonic production of all higher menquinones. High menaquinone-4 intake induces very high menaquinone-8 concentrations, both in the colonic contents as well as in the liver. These data suggest that menaquinone-4 may be converted into menaquinone-8 (but not into other menaquinones) via a metabolic pathway which has not been reported previously.
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