利用对硝基苯酚法，在体外ＢＭＰ作用的牙周膜细胞和牙龈成纤维细胞进行碱性磷酸酶活性的测定。结果表明，牙周膜细胞的碱性磷酸酶活性明显高于牙龈成纤维细胞。经骨形成蛋白作用后，牙周膜细胞的碱性磷酸酶活性有所升高；在甲状旁腺素的作用下，经ＢＭＰ作用过的牙周膜细胞的碱性磷酸酶活性有较大幅度地下降，而牙龈成纤维细胞无明显变化，提示牙周膜细胞中可能存在有骨形成蛋白的靶细胞。 Alkaline phosphatase activity was measured using p-nitrophenol method, periodontal ligament cells with in vitro BMP action and gingival fibroblasts. The results showed that the alkaline phosphatase activity of periodontal ligament cells was significantly higher than that of gingival fibroblasts. Alkaline phosphatase activity of periodontal ligament cells increased after osteogenesis, while alkaline phosphatase activity of periodontal ligament cells treated with BMP was greater under the action of parathyroid hormone However, there was no significant change in gingival fibroblasts, suggesting that there may be target cells of bone morphogenetic protein in periodontal ligament cells.