Calcium influx is not required for TRH to elevate free cytoplasmic calcium in GH3 cells.
Calcium influx is not required for TRH to elevate free cytoplasmic calcium in GH3 cells.
复制标题
TRH 不需要钙流入来升高 GH3 细胞中的游离细胞质钙。
作者：
Marvin C. Gershengorn;C. Thaw
TRH刺激催乳素分泌被认为是由细胞质游离Ca 2+升高介导的。然而，是否TRH诱导的细胞外Ca 2+内流是必需的，以提高胞浆Ca 2+仍然存在争议。我们用胞内捕获的荧光指示剂Quin 2测量了GH 3细胞中细胞质游离Ca 2+浓度。在含有1.5 mM Ca 2+的培养基中孵育的未刺激细胞中，细胞质游离Ca 2+浓度为118 +/- 18 nM（平均值+/- SD）。TRH（1 μ M）引起细胞质游离Ca 2+的快速瞬时升高，估计至少为500 nM。高的细胞外K+诱导细胞外Ca ~（2+）内流，引起胞浆游离Ca ~（2+）升高，其幅度和持续时间均大于TRH。当细胞在含有3 mM EGTA的培养基中孵育时，K+去极化诱导的游离胞质Ca 2+增加被取消。相比之下，TRH诱导的增加不受3 mM EGTA或高K+或两者的培养基中孵育细胞的影响; EGTA和高K+的培养基中孵育细胞消除了Ca 2+流入的电化学驱动力。这些数据表明，Ca 2+内流是不需要TRH诱导的GH 3细胞胞质游离Ca 2+的升高。我们的结论是，在GH 3细胞中，TRH诱导细胞质游离Ca 2+的升高，从而通过动员细胞内Ca 2+刺激催乳素分泌。
TRH stimulation of prolactin secretion is thought to be mediated by an elevation of free cytoplasmic Ca2+. However, whether TRH-induced influx of extracellular Ca2+ is required to elevate cytoplasmic Ca2+ remains controversial. We measured cytoplasmic free Ca2+ concentration in GH3 cells with an intracellularly trapped fluorescent indicator, Quin 2. In unstimulated cells incubated in medium containing 1.5 mM Ca2+, cytoplasmic free Ca2+ concentration was 118 +/- 18 nM (mean +/- SD). TRH (1 microM) caused a rapid transient elevation of free cytoplasmic Ca2+ to a level estimated to be at least 500 nM. High extracellular K+, which induces extracellular Ca2+ influx, caused an elevation of free cytoplasmic Ca2+ which was greater and longer in duration that that caused by TRH. When cells were incubated in medium containing 3 mM EGTA, the K+ depolarization-induced increase in free cytoplasmic Ca2+ was abolished. By contrast, the TRH-induced increase was not affected by incubating cells in medium with 3 mM EGTA, or high K+, or both; incubation of cells in medium with EGTA and high K+ abolishes the electrochemical driving force for Ca2+ influx. These data demonstrate that Ca2+ influx is not required for TRH-induced elevation of free cytoplasmic Ca2+ in GH3 cells. We conclude that in GH3 cells TRH induces an elevation of free cytoplasmic Ca2+ leading to stimulated prolactin secretion by mobilizing cellular Ca2+.
受体介导的质膜相关钙的释放以及培养的垂体细胞中促甲状腺素释放激素刺激钙的吸收。
DOI：
--
发表时间：
1981
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Tan,KN;TashjianJr,AH
通讯作者：
TashjianJr,AH
促甲状腺激素释放激素从 GH3 垂体细胞的内质网和线粒体动员 Ca2：通过基于毛地黄皂苷透化的方法表征细胞 Ca2 池。
DOI：
10.1073/pnas.79.20.6294
发表时间：
1982
影响因子：
11.1
作者：
Ronning,SA;Heatley,GA;Martin,TF
通讯作者：
Martin,TF