Affiliations: Central Research Institute, Mizkan Group Corporation,
2-6 Nakamura-Cho, Handa-Shi, Aichi. 475-8585, Japan. Tel.: +84 569 24 5075;
E-mail: [email protected]
Abstract: The effect of menaquinone-7 (MK-7) on bone components and bone
resorbing factors induced-bone resorption using the femoral-diaphyseal and
– metaphyseal tissues obtained from elderly female rats in vitro were
examined. Calcium content, alkaline phosphatase activity and deoxyribonucleic
acid (DNA) in the diaphyseal and metaphyseal tissues in elderly females rats
were significantly decreased as compared with that of young rats, indicating
that aging causes a deterioration of bone formation. The presence of MK-7
(10^{-6}-10^{-5} M) caused a significant
prevention of reduction of biochemical components. On the other hand, the
bone-resorbing factor, parathyroid hormone (1–34) (PTH;
10^{-7} M) and prostaglandin E_{2}
(PGE_{2}; 10^{-5} M) caused a significant
decrease in calcium content in the diaphyseal and metaphyseal tissues. This
decreases was completely inhibited in the presence of MK-7
(10^{-7}-10^{-5} M). In addition, MK-7
(10^{-7}-10^{-5} M) completely prevented
the PTH (10^{-7} M) or PGE_{2}
(10^{-5} M) induced increases in medium glucose consumption
and lactic acid production by bone tissues, Furthermore, the effect of the
prolonged intake of dietary MK-7 on bone loss in ovariectomized rats was
investigated. As a result, it was found that the intake of experimental diets
containing the fermented soybean (natto) with supplemental MK-7 caused
significant elevations of MK-7 and γ-carboxylated
osteocalcin concentration, a bio marker of bone formation, in the serum of both
ovariectomized rats and normal subjects, suggesting that MK-7 may play an
important role in the prevention of age-related bone loss.
Keywords: menaquinone-7 (MK-7), vitamin K[TeX:] _{2}, bone formation, bone resorption, osteocalcin, osteoporosis
Journal: BioFactors, vol. 22, no. 1-4, pp. 5-19, 2004
