Comparative metabolism of phylloquinone and menaquinone-9 in rat liver.
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 mumol 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 mumol/kg diet), whereas at high dietary concentrations (5.6 mumol/kg diet) they were equally effective.
Will
B H
BH
Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison 53706.
Suttie
J W
JW
D000284:Administration, Oral; D000818:Animals; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D011516:Prothrombin / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D014812:Vitamin K / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D010837:Vitamin K 1 / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D024482:Vitamin K 2 / Q000031:analogs & derivatives*
D024482:Vitamin K 2; D014812:Vitamin K; C073355:menaquinone 9; D010837:Vitamin K 1; D011516:Prothrombin