Ehara Y, Takahashi H, Hanahisa Y, Yamaguchi M
Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, Japan.
Res Exp Med (Berl). 1996;196(3):171-8. doi: 10.1007/BF02576839.
The effect of vitamin K2 (menaquinone-7) on bone metabolism in the femoral-metaphyseal tissues of normal and skeletal-unloaded rats was investigated. Skeletal unloading was designed using a model of hindlimb suspension; the rats were fed for the 4 days of unloading. The metaphyseal tissues obtained from normal and skeletal-unloaded rats were cultured for 48 h in medium containing either vehicle or vitamin K2 (10(-6) and 10(-5) M). The presence of vitamin K2 (10(-5) M) caused a significant increase in alkaline phosphatase activity and calcium content in the metaphyseal tissues from normal rats. Such an effect was not seen in the bone tissues from skeletal-unloaded rats. Additionally, the presence of zinc sulfate (10(-5) M) in effective concentration produced a significant increase in alkaline phosphatase activity and calcium content in the metaphyseal tissues from normal and skeletal-unloaded rats. In the presence of vitamin K2 (10(-5) M), the stimulatory effect of zinc sulfate on bone calcium content was appreciably enhanced; although this effect was completely abolished by cycloheximide (10(-6) M), an inhibitor of protein synthesis. This study demonstrates that the effect of vitamin K2 (menaquinone-7) on trabecular bone calcification in rats with skeletal unloading-induced osteopenia is enhanced by zinc in vitro. The enhancement with zinc may be based on a newly synthesized protein in the bone tissues.
研究了维生素K2（甲萘醌-7）对正常和骨骼失载大鼠股骨-干骺端组织骨代谢的影响。采用后肢悬吊模型设计骨骼失载；在失载的4天内喂养大鼠。从正常和骨骼失载大鼠获得的干骺端组织在含有载体或维生素K2（10^(-6)和10^(-5) M）的培养基中培养48小时。维生素K2（10^(-5) M）的存在导致正常大鼠干骺端组织中碱性磷酸酶活性和钙含量显著增加。在骨骼失载大鼠的骨组织中未观察到这种效应。此外，有效浓度的硫酸锌（10^(-5) M）使正常和骨骼失载大鼠干骺端组织中的碱性磷酸酶活性和钙含量显著增加。在维生素K2（10^(-5) M）存在下，硫酸锌对骨钙含量的刺激作用明显增强；尽管这种作用被蛋白质合成抑制剂环己酰亚胺（10^(-6) M）完全消除。本研究表明，在体外，锌可增强维生素K2（甲萘醌-7）对骨骼失载诱导的骨质疏松大鼠小梁骨钙化的作用。锌的增强作用可能基于骨组织中新合成的蛋白质。
