Time-dependent effects of vitamin K2 (menatetrenone) on bone metabolism in postmenopausal women.
Vitamin K is known to mediate carboxylation of glutamyl residues of osteocalcin. We evaluated the effects of vitamin K2 (menatetrenone) treatment (45 mg/day) for 48 weeks on the markers of bone formation and resorption, bone mineral density (BMD), and the incidence of vertebral fractures in 34 Japanese postmenopausal women (aged 48-82 years). Serum levels of alkaline phosphatase (ALP) increased gradually and became significant at 48 weeks after menatetrenone treatment, while urinary excretion of deoxypyridinoline (DPD) decreased transiently but significantly at 4 weeks. Serum levels of both intact osteocalcin (OC) and carboxylated OC (Gla-OC) increased rapidly and significantly within 4 weeks and sustained their high values up to 48 weeks after the treatment, while those of undercarboxylated OC (Glu-OC) decreased reciprocally. These results can be interpreted to suggest that Glu-OC was converted to Gla-OC in vivo. On the other hand, lumbar BMD values showed no significant change and only one subject with a previous vertebral fracture had one newly occurring vertebral fracture. These results indicate that menatetrenone treatment of postmenopausal women constantly elevates bone formation markers as well as converts Glu-OC to Gla-OC. Thus, vitamin K2 treatment may promote bone formation, at least as measured biochemically in these subjects.
Ozuru
Rieko
R
Third Division, Department of Medicine, Kobe University School of Medicine, Kobe 650-0017, Japan.
Sugimoto
Toshitsugu
T
Yamaguchi
Tohru
T
Chihara
Kazuo
K
D000368:Aged; D000369:Aged, 80 and over; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D017698:Postmenopause / Q000502:physiology*; D016103:Spinal Fractures / Q000453:epidemiology; D013997:Time Factors; D024482:Vitamin K 2 / Q000627:therapeutic use*
D015675:Osteocalcin; D024482:Vitamin K 2; D002245:Carbon Dioxide; C041069:carboxyl radical