Shoback D, Thatcher J, Leombruno R, Brown E
Endocrinology. 1983 Jul;113(1):424-6. doi: 10.1210/endo-113-1-424.
We studied the effects of varying extracellular concentrations of Ca++ and Mg++ on cytosolic Ca++ concentration and PTH release by incorporating the Ca++-sensitive, fluorescent dye "QUIN 2" into dispersed bovine parathyroid cells. Increasing extracellular Ca++ from 0.5 to 2.0 mM led to a dose-dependent increase in cytosolic Ca++ from 179 +/- 8 to 646 +/- 68 nM (mean +/- SE, N = 13; P less than 0.01), which correlated closely (r = -.987, P less than .001) with the suppression of PTH secretion by the same Ca++ concentrations. Raising extracellular Mg++ from 0.5 to 3 mM also caused a dose-related increase in cytosolic Ca++ from 176 +/- 10 to 277 +/- 15 nM (N = 12, P less than 0.01) which correlated (r = -.959, P less than .01) with inhibition of PTH release. These results show a close inverse relationship between cytosolic Ca++ and PTH release with alterations in extracellular Ca++ or Mg++. Cytosolic Ca++ may, therefore, act as a second messenger mediating the effects of these divalent cations on PTH release.
我们通过将对钙离子敏感的荧光染料“喹啉2”导入分散的牛甲状旁腺细胞，研究了细胞外不同浓度的钙离子（Ca++）和镁离子（Mg++）对胞质钙离子浓度及甲状旁腺激素（PTH）释放的影响。将细胞外钙离子浓度从0.5 mM增至2.0 mM，可使胞质钙离子浓度呈剂量依赖性升高，从179±8 nM增至646±68 nM（均值±标准误，N = 13；P < 0.01），这与相同钙离子浓度对甲状旁腺激素分泌的抑制作用密切相关（r = -0.987，P < 0.001）。将细胞外镁离子浓度从0.5 mM提高至3 mM，也会使胞质钙离子浓度呈剂量相关性升高，从176±10 nM增至277±15 nM（N = 12，P < 0.01），这与甲状旁腺激素释放受到抑制相关（r = -0.959，P < 0.01）。这些结果表明，随着细胞外钙离子或镁离子浓度的改变，胞质钙离子与甲状旁腺激素释放之间存在密切的负相关关系。因此，胞质钙离子可能作为第二信使，介导这些二价阳离子对甲状旁腺激素释放的作用。
