Lundgren T, Stenport V, Wetter A, Linde A
Department of Oral Biochemistry, Faculty of Odontology, Göteborg University, Sweden.
Calcif Tissue Int. 1998 Mar;62(3):255-9. doi: 10.1007/s002239900426.
Even though indirect evidence indicates that PTH exerts an anabolic effect on dentinogenesis, the existence of PTH receptors and any second-messenger response in odontoblasts have not been demonstrated. The aim of this study was to investigate whether rat incisor odontoblasts express PTH receptors, and to identify which second messenger pathway the hormone may activate. Odontoblasts were dissected from rat incisors. Amino-terminal (1-34) fragment rat PTH [rPTH(1-34)] conjugated to fluorescein isothiocyanate visualized receptor sites on the cell surface. Upon incubation of odontoblasts with rPTH(1-34), cAMP formation was increased. However, no fluctuations in intracellular calcium activity were observed upon rPTH(1-34) stimulation when using Fura-2 as a Ca2+ probe. In long-time incubations, stimulation with PTH(1-34) upregulated APase activity. The results demonstrate that rPTH(1-34) evokes an anabolic response in dentinogenically active odontoblasts, and that this may be mediated through the protein kinase A/cAMP pathway, whereas no indications for Ca2+ as a second messenger were evident.
尽管间接证据表明甲状旁腺激素（PTH）对牙本质生成具有合成代谢作用，但尚未证实成牙本质细胞中存在PTH受体以及任何第二信使反应。本研究的目的是调查大鼠切牙成牙本质细胞是否表达PTH受体，并确定该激素可能激活哪种第二信使途径。从大鼠切牙中分离出成牙本质细胞。与异硫氰酸荧光素偶联的氨基末端（1-34）片段大鼠PTH[rPTH(1-34)]可使细胞表面的受体位点可视化。用rPTH(1-34)孵育成牙本质细胞后，细胞内cAMP生成增加。然而，当使用Fura-2作为Ca2+探针时，rPTH(1-34)刺激后未观察到细胞内钙活性的波动。在长时间孵育中，用PTH(1-34)刺激可上调碱性磷酸酶（APase）活性。结果表明，rPTH(1-34)在具有牙本质生成活性的成牙本质细胞中引发合成代谢反应，且这可能是通过蛋白激酶A/cAMP途径介导的，而未发现Ca2+作为第二信使的明显迹象。
