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J Nutr. 2008 Mar;138(3):492-6.

Age and dietary form of vitamin K affect menaquinone-4 concentrations in male Fischer 344 rats.

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1
Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. sarah.booth@tufts.edu

Abstract

Phylloquinone, the primary dietary form of vitamin K, is converted to menaquinone-4 (MK-4) in certain tissues. MK-4 may have tissue-specific roles independent of those traditionally identified with vitamin K. Fischer 344 male rats of different ages (2, 12, and 24 mo, n = 20 per age group) were used to compare the conversion of phylloquinone to MK-4 with an equivalent dose of another dietary form of vitamin K, 2',3'-dihydrophylloquinone. Rats were age- and diet-group pair-fed phylloquinone (198 +/- 9.0 microg/kg diet) or dihydrophylloquinone (172 +/- 13.0 microg/kg diet) for 28 d. MK-4 was the primary form of vitamin K in serum, spleen, kidney, testes, bone marrow, and brain myelin fractions, regardless of age group. MK-4 concentrations were significantly lower in kidney, heart, testes, cortex (myelin), and striatum (myelin) in the dihydrophylloquinone diet group compared with the phylloquinone diet group (P < 0.05). The MK-4 concentrations in 2-mo-old rats were lower in liver, spleen, kidney, heart, and cortex (myelin) but higher in testes compared with 24-mo-old rats (P < 0.05). However, there were no age-specific differences in MK-4 concentrations among the rats fed the 2 diets. These data suggest that dihydrophylloquinone, which differs from phylloquinone in its side phytyl chain, is absorbed but its intake results in less MK-4 in certain tissues. Dihydrophylloquinone may be used in models for the study of tissue-specific vitamin K deficiency.

PMID:
18287355
[Indexed for MEDLINE]
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