Oral Administration of Cal K_2 Containing Menaquinone-4 (Vitamin K_2) Enhances Serum r-Carboxylated Osteocalcin and Biochemical Components in the Femoral Tissues of Rats

The effects of menaquinone-4 (MK-4; vitamin K_2) supplemented egg shell calcium (Cat K_2) on bone components in the femoral-diaphyseal (cortical bone) and-metaphyseal (trabecular bone) tissues of rats was investigated. Cal K_2 contained calcium carbonate (Ca 100mg/g) and MK-4 (593μg/g). Rats were orally administered a solution of Cat K_2 (10, 25, or 50mg/ml/100g body weight) or placebo (without MK-4, 50mg/ml/100g body weight) once daily for 7 days. The serum r-carboxylated osteocalcin concentration, which is produced in osteoblastic cells, was significantly increased after the administration of Cal K_2 (50mg/100g body weight) as compared with that in the control group or placebo-control group without MK-4. Calcium content and alkaline phosphatase activity in the femoral-diaphyseal tissues were significantly increased after Cal K_2 (25 or 50mg/100g) as compared with that in the placebo-control group. Femoral-metaphyseal calcium content was significantly increased after the administration of Cal K_2 (25 or 50mg/100g) as compared with that in the control group. DNA content in the femoral-diaphy-seal and -metaphyseal tissues was significantly increased after the administration of Cal K_2 (50mg/100g) as compared with that in the control or placebo-controlled group. This study demonstrates that the oral administration of Cal K_2 containing MK-4 has anabolic effects on bone components in rats. Supplemental Cal K_2 may have a role in the prevention of bone loss with aging.