细胞外钾离子和血管紧张素II对肾上腺球状带细胞胞质钙离子及类固醇生成的影响。

The effects of extracellular K+ and angiotensin II on cytosolic Ca++ and steroidogenesis in adrenal glomerulosa cells.

作者信息

Braley L, Menachery A, Brown E, Williams G

出版信息

Biochem Biophys Res Commun. 1984 Sep 17;123(2):810-5. doi: 10.1016/0006-291x(84)90302-4.

Abstract

We evaluated changes in cytosolic calcium concentration (Ca++) and steroidogenesis in rat adrenal glomerulosa cells (GC) stimulated with potassium (K+) or angiotensin II (AII). Cytosolic Ca++ concentration was determined using the Ca++-sensitive, fluorescent dye QUIN 2. Raising extracellular K+ increased cytosolic Ca++ from 267 +/- 23 nM at 3.7 mM K+ to a maximum of 377 +/- 40 nM at 8.7 mM K+ (p less than 0.01, N = 23). AII also increased cytosolic Ca++ from 238 +/- 20 nM to a maximum of 427 +/- 42 nM at 10(-7) M (p less than 0.01, N = 16). In parallel studies, K+ and AII stimulated aldosterone secretion from QUIN 2-loaded GC at concentrations similar to those which raised cytosolic Ca++. QUIN 2-loaded cells were as responsive steroidogenically as unloaded cells and showed trypan blue exclusion of 98% suggesting that QUIN 2 did not compromise cellular viability. These results provide direct support for a role of cytosolic Ca++ as a second messenger during stimulation of aldosterone secretion by both K+ and AII.

摘要

我们评估了用钾离子（K+）或血管紧张素II（AII）刺激大鼠肾上腺球状带细胞（GC）时，胞质钙浓度（Ca++）的变化以及类固醇生成情况。使用对Ca++敏感的荧光染料喹啉-2（QUIN 2）测定胞质Ca++浓度。将细胞外K+浓度从3.7 mM K+时的267±23 nM提高到8.7 mM K+时的最大值377±40 nM（p<0.01，N = 23）。AII也使胞质Ca++浓度从238±20 nM增加到10-7 M时的最大值427±42 nM（p<0.01，N = 16）。在平行研究中，K+和AII在类似于提高胞质Ca++浓度的浓度下刺激加载了QUIN 2的GC分泌醛固酮。加载了QUIN 2的细胞在类固醇生成方面与未加载的细胞一样有反应，并且台盼蓝排斥率为98%，这表明QUIN 2不会损害细胞活力。这些结果为胞质Ca++在K+和AII刺激醛固酮分泌过程中作为第二信使的作用提供了直接支持。