Manolagas S C, Burton D W, Deftos L J
J Biol Chem. 1981 Jul 25;256(14):7115-7.
Rat osteogenic sarcoma cells which have osteoblast properties including the ability to form bone and to mineralize were recently found to possess specific cytoplasmic receptors for 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). We have examined now the effect of 1,25(OH)2D3 and other vitamin D3 metabolites on the alkaline phosphatase of such cell lines. We found in two cell lines cultured in the presence of 10(-7) M 1,25(OH)2D3 a 3-fold increase in intracellular alkaline phosphatase activity and a 6-fold increase in secreted alkaline phosphatase activity. The cellular response occurred in a dose-dependent fashion at a range of 10(-9) to 10(-7) M. In a third cell line, which does not possess the specific receptor for 1,25(OH)2D3, we could not detect stimulation of alkaline phosphatase. Vitamin D3, 25-dihydroxyvitamin D3, and 24,25-dihydroxyvitamin D3 at 10(-7) M had no effect on alkaline phosphatase. The effect of 1,25(OH)2D3 was enhanced in the presence of increased calcium. In view of the postulated role for alkaline phosphatase in calcification, we speculate that the stimulatory effect of 1,25(OH)2D3 on the alkaline phosphatase activity of osteoblast-like cells indicates a direct involvement of 1,25(OH)2D3 in bone mineralization.
最近发现具有成骨细胞特性（包括形成骨和矿化能力）的大鼠骨肉瘤细胞拥有1,25 - 二羟基维生素D3（1,25(OH)2D3）的特异性细胞质受体。我们现在研究了1,25(OH)2D3和其他维生素D3代谢产物对这类细胞系碱性磷酸酶的影响。我们发现在两种细胞系中，当在10(-7) M的1,25(OH)2D3存在下培养时，细胞内碱性磷酸酶活性增加了3倍，分泌的碱性磷酸酶活性增加了6倍。细胞反应在10(-9)至10(-7) M的范围内呈剂量依赖性。在第三种不拥有1,25(OH)2D3特异性受体的细胞系中，我们未检测到碱性磷酸酶的刺激作用。10(-7) M的维生素D3、25 - 二羟基维生素D3和24,25 - 二羟基维生素D3对碱性磷酸酶没有影响。在钙增加的情况下，1,25(OH)2D3的作用增强。鉴于碱性磷酸酶在钙化中的假定作用，我们推测1,25(OH)2D3对成骨样细胞碱性磷酸酶活性的刺激作用表明1,25(OH)2D3直接参与骨矿化。
