Hara K, Akiyama Y, Tomiuga T, Kobayashi M, Nakamura T, Tajima T
Department of Drug Research II, Eisai Co., Ltd., Tokyo, Japan.
Nihon Yakurigaku Zasshi. 1994 Aug;104(2):101-9. doi: 10.1254/fpj.104.101.
To evaluate whether the vitamin D3 level in the plasma influences the inhibitory effect of vitamin K2 on bone loss, vitamin K2 (25 mg/kg/day) was administered to ovariectomized (OVX) rats fed a diet containing vitamin D3 (V.D.(+)) or a diet deficient in vitamin D3 (V.D.(-)). After 3 months of treatment, the plasma 25-OH-vitamin D3 (25-OH-D3) level in the V.D(-)-sham group was about 1/3 of that in the V.D(+)-sham group. The plasma calcium level and alkaline phosphatase activity were also significantly lower in the V.D(-)-sham group than in the V.D(+)-sham group. In the V.D(+) group, the plasma 25-OH-D3 level in the vitamin K2 group was about 1.5 times higher than that in the OVX-control group. Ovariectomy resulted in a significant decrease in bone density, bone mineral content (BMC) and bone mineral density (BMD) of femurs in both the V.D(+) and V.D(-) groups. In the V.D(-) group, vitamin K2 had no marked effect on the bone loss. In the V.D(+) group, the bone density and BMD in the mid portion of the femur were significantly increased by vitamin K2 treatment. These findings suggest that the effect of vitamin K2 on bone loss is affected by the vitamin D3 level in the plasma.
为评估血浆中维生素D3水平是否会影响维生素K2对骨质流失的抑制作用，将维生素K2（25毫克/千克/天）给予喂食含维生素D3饮食（V.D.(+)）或缺乏维生素D3饮食（V.D.(-)）的去卵巢（OVX）大鼠。治疗3个月后，V.D(-)-假手术组的血浆25-羟基维生素D3（25-OH-D3）水平约为V.D(+)-假手术组的1/3。V.D(-)-假手术组的血浆钙水平和碱性磷酸酶活性也显著低于V.D(+)-假手术组。在V.D(+)组中，维生素K2组的血浆25-OH-D3水平约为OVX-对照组的1.5倍。去卵巢导致V.D(+)和V.D(-)组大鼠股骨的骨密度、骨矿物质含量（BMC）和骨矿物质密度（BMD）显著降低。在V.D(-)组中，维生素K2对骨质流失无明显作用。在V.D(+)组中，维生素K2治疗显著增加了股骨中部的骨密度和BMD。这些发现表明，维生素K2对骨质流失的作用受血浆中维生素D3水平的影响。
