Difference in the metabolism of vitamin K between liver and bone in vitamin K-deficient rats.
The difference between vitamin K metabolism in the liver and that in the bone of vitamin K-deficient rats was examined. After 17 d administration of vitamin K-deficient food, vitamin K in the liver was almost depleted, and prothrombin time (PT) was prolonged. Serum total osteocalcin level was slightly decreased by vitamin K deficiency, whereas serum undercarboxylated osteocalcin level did not change. The level of menaquinone (MK)-4 as well as that of phylloquinone was decreased, but approximately 40 % of the initial level still existed in the femur after the 17 d period. A single-dose administration of vitamin K (250 nmol/kg body weight) markedly increased vitamin K level in the liver but not in the femur. These results suggest that the turnover of vitamin K in the bone is slower than that in the liver, and bone metabolism may be little affected by the short period of intake of vitamin K-deficient food. However, intake of a larger amount of vitamin K is required for its accumulation in the bone than in the liver. Furthermore, the counteracting effect of MK-7 on prolonged PT in vitamin K-deficient rats was found to be higher than phylloquinone or MK-4.
Sato
Toshiro
T
Chemicals Research Laboratories, Honen Corporation, Iwata-gun, Shizuoka, Japan. tosato@honen.co.jp
Ohtani
Yutaka
Y
Yamada
Yoko
Y
Saitoh
Sanshiroh
S
Harada
Hiroshi
H
D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D003487:Cyanoacrylates / Q000494:pharmacology; D007210:Indoleacetic Acids; D008099:Liver / Q000378:metabolism*; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time; D051381:Rats; D017207:Rats, Sprague-Dawley; D014812:Vitamin K / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D010837:Vitamin K 1 / Q000097:blood / Q000494:pharmacology; D024482:Vitamin K 2 / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D014813:Vitamin K Deficiency / Q000378:metabolism*
D003487:Cyanoacrylates; D007210:Indoleacetic Acids; D015675:Osteocalcin; D024482:Vitamin K 2; D014812:Vitamin K; C007166:cyacrin; C030814:menatetrenone; C079343:MK 410; D010837:Vitamin K 1; C062629:menaquinone 7