Elevation of bovine endothelial cell angiotensin converting enzyme by cationophores and inhibition by ouabain.
Elevation of bovine endothelial cell angiotensin converting enzyme by cationophores and inhibition by ouabain.
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阳离子载体升高牛内皮细胞血管紧张素转换酶并哇巴因抑制。
DOI：
10.1016/0167-4889(90)90168-d
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Fanburg,BL
中科院分区：
文献类型：
--
作者：
Dasarathy,Y;Fanburg,BL
我们最近报道，钙离子载体A23187引起的血管紧张素转换酶（ACE）活性的牛肺动脉内皮细胞培养的几倍的升高，这种升高是依赖于细胞外钙。现在我们已经观察到莫能菌素，一种钠离子载体，也能提高这些细胞的ACE活性。ACE的这种升高不受0.2 mM EGTA或钙通道抑制剂硝苯地平的抑制，莫能菌素不改变细胞内钙通过荧光法评估的Fura-2 AM负载细胞。当汇合的内皮细胞与莫能菌素或A23187在10-20 nM哇巴因（一种Na+ K+-ATP酶的特异性抑制剂）的存在下孵育时，由两种离子载体产生的ACE升高被完全消除。浓度大于10 nM的哇巴因也抑制ACE活性的基线水平。Fura-2 AM负载细胞的Ca 2+测定结果表明，哇巴因对A23187产生的Ca 2+内流无影响。ACE的升高似乎需要新的蛋白质合成，因为0.1 μg/ml放线菌酮抑制莫能菌素和A23187产生的升高。其他钠转运抑制剂如阿米洛利或布美他尼对莫能菌素引起的ACE升高没有影响。这些结果表明，牛血管内皮细胞的ACE水平在培养的阳离子调节，并可能受到哇巴因敏感的Na+ K+-ATP酶。
We recently reported that calcium ionophore A23187 causes a several-fold elevation of angiotensin converting enzyme (ACE) activity of bovine pulmonary artery endothelial cells in culture and that this elevation is dependent upon extracellular calcium. Now we have observed that monensin, a sodium ionophore, also elevates the ACE activity of these cells. This elevation in ACE was not inhibited by 0.2 mM EGTA or the calcium channel inhibitor nifedipine, and monensin did not alter intracellular calcium as measured by fluorimetric assessment of fura-2 AM-loaded cells. When confluent endothelial cells were incubated with monensin or A23187 in the presence of 10–20 nM ouabain, a specific inhibitor of Na+ K+-ATPase, the elevation in ACE produced by both of the ionophores was totally eliminated. Concentrations of ouabain greater than 10 nM also inhibited baseline levels of ACE activity. Ca 2+ measurements of fura-2 AM-loaded cells showed that ouabain had no effect on the influx of Ca 2+ produced by A23187. The elevation of ACE seemed to require new protein synthesis, since 0.1 μg/ml cycloheximide inhibited the elevation produced by monensin and A23187. Other sodium transport inhibitors such as amiloride or bumetanide had no effect on ACE elevation caused by monensin. These results suggest that ACE levels of bovine endothelial cells in culture are under cation regulation and may be modulated by ouabain-sensitive Na+ K+-ATPase.