Thyrotropin-releasing hormone increases cytosolic free Ca2+ in clonal pituitary cells (GH3 cells): direct evidence for the mobilization of cellular calcium.
Thyrotropin-releasing hormone increases cytosolic free Ca2+ in clonal pituitary cells (GH3 cells): direct evidence for the mobilization of cellular calcium.
复制标题
促甲状腺蛋白释放激素会增加克隆垂体细胞（GH3细胞）中的胞质游离Ca2+：动员细胞钙的直接证据。
DOI：
10.1083/jcb.99.1.83
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发表时间：
1984-07
影响因子：
7.8
通讯作者：
Wollheim, C B
中科院分区：
文献类型：
--
作者：
Schlegel, W;Wollheim, C B
细胞表面受体激活后胞浆内游离钙离子浓度的变化被认为是介导多种细胞反应的因素。用特异的钙离子螯合剂Quin2作为细胞内荧光探针，测定了克隆大鼠垂体细胞--GH3细胞胞浆中的钙离子浓度。我们证明，在纳摩尔浓度的促甲状腺激素释放激素(TRH)会导致细胞内钙离子的快速和短暂的增加。在有EGTA存在的无钙介质中，这种增加发生在低于胞浆浓度的细胞外钙水平，而钙通道阻滞剂维拉帕米不能阻止这种增加。K+能模拟TRH对催乳素释放的作用，但只有在胞外游离钙离子存在的情况下才能使细胞内钙离子浓度升高，这种作用可被维拉帕米所阻断。这些数据表明，先前研究提出的TRH作用引起的细胞内钙的动员实际上会导致细胞内游离钙的增加。这一反应的动力学特征强调了胞内游离钙离子在刺激-分泌耦合中的关键作用。
Changes in the cytosolic free Ca2+ concentration following cell surface receptor activation have been proposed to mediate a wide variety of cellular responses. Using the specific Ca2+ chelator quin2 as a fluorescent intracellular probe, we measured the Ca2+ levels in the cytosol of clonal rat pituitary cells, GH3 cells. We demonstrate that thyrotropin-releasing hormone (TRH) at nanomolar concentrations leads to a rapid and transient increase in cytosolic Ca2+. This increase was found to occur in Ca2+-free media in the presence of EGTA, thus at extracellular Ca2+ levels that are below the cytosolic concentrations, and was not prevented by verapamil, a Ca2+ channel blocker. Depolarization of GH3 cells with K+, which can mimic the action of TRH on prolactin release, increased cytosolic Ca2+ levels only in the presence of free extracellular Ca2+, and this increase could be blocked by verapamil. These data show that the mobilization of intracellular Ca2+ due to TRH action that has been proposed by previous studies actually leads to an increase in cytosolic free Ca2+. The kinetic features of this response emphasize the key role of cytosolic free Ca2+ in stimulus-secretion coupling.