Rao L G, Wylie J N, Kung Sutherland M S, Murray T M
Calcium Research Laboratory, St Michael's Hospital, Toronto, Ontario, Canada.
J Endocrinol. 1996 Jan;148(1):181-7. doi: 10.1677/joe.0.1480181.
We tested the effect of osteoblastic differentiation on the interactive effects of 17 beta-oestradiol (E2) and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on alkaline phosphatase activity. As cell models we utilized the more differentiated human osteosarcoma (SaOS) cells that had been cultured for 6 days in medium containing 10 nM dexamethasone (Dex) (SaOS+Dex cells) and the less differentiated cells cultured in the absence of Dex (SaOS-Dex cells). The cells were challenged with 1,25(OH)2D3 in the presence or absence of Dex for 24 h and then with E2 for an additional 24 h. In SaOS-Dex cells, alkaline phosphatase activity remained constant over the 48-h period and was not significantly affected by E2, 1,25(OH)2D3 or 1,25(OH)2D3+E2 treatment. On the other hand, in SaOS+Dex cells, 1,25(OH)2D3 and E2+1,25(OH)2D3 stimulated alkaline phosphatase activity (ANOVA, F = 154.2, P < 0.0001) with the maximal response at 48 h (P < 0.01). In SaOS+Dex cells, 1,25(OH)2D3 had dose-dependent stimulatory effects which were strongly enhanced by 10 nM E2 (ANOVA, F = 46.0, P < 0.001). Studies on dose-dependent effects of E2, in the presence or absence of 100 nM 1,25(OH)2D3, revealed that in the presence of 1,25(OH)2D3, the E2 dose-response curve was biphasic in SaOS+Dex cells (ANOVA, F = 3.40, P < 0.005), with maximum stimulation at 10 nM E2 (P < 0.01). The specificity of E2 was verified using the inactive 17 alpha-oestradiol and the oestrogen antagonist, tamoxifen. These data indicate that E2 and 1,25(OH)2D3 have positive interactive effects on alkaline phosphatase activity in human osteoblasts, and suggest that the expression of this interaction is dependent on the stage of differentiation of the cells.
我们测试了成骨细胞分化对17β-雌二醇（E2）和1,25-二羟基维生素D3（1,25(OH)2D3）对碱性磷酸酶活性的交互作用的影响。作为细胞模型，我们使用了在含有10 nM地塞米松（Dex）的培养基中培养6天的分化程度更高的人骨肉瘤（SaOS）细胞（SaOS+Dex细胞）以及在无Dex条件下培养的分化程度较低的细胞（SaOS-Dex细胞）。细胞在有或无Dex的情况下用1,25(OH)2D3刺激24小时，然后再用E2刺激24小时。在SaOS-Dex细胞中，碱性磷酸酶活性在48小时内保持恒定，并且不受E2、1,25(OH)2D3或1,25(OH)2D3+E2处理的显著影响。另一方面，在SaOS+Dex细胞中，1,25(OH)2D3和E2+1,25(OH)2D3刺激碱性磷酸酶活性（方差分析，F = 154.2，P < 0.0001），在48小时时达到最大反应（P < 0.01）。在SaOS+Dex细胞中，1,25(OH)2D3具有剂量依赖性刺激作用，10 nM E2可强烈增强这种作用（方差分析，F = 46.0，P < 0.001）。对在有或无100 nM 1,25(OH)2D3情况下E2的剂量依赖性作用的研究表明，在存在1,25(OH)2D3时，SaOS+Dex细胞中的E2剂量反应曲线呈双相性（方差分析，F = 3.40，P < 0.005），在10 nM E2时刺激作用最大（P < 0.01）。使用无活性的17α-雌二醇和雌激素拮抗剂他莫昔芬验证了E2的特异性。这些数据表明，E2和1,25(OH)2D3对人成骨细胞中的碱性磷酸酶活性具有正向交互作用，并表明这种相互作用的表达取决于细胞的分化阶段。
