Effect of insulin on intracellular pH in frog skeletal muscle fibers.
Effect of insulin on intracellular pH in frog skeletal muscle fibers.
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胰岛素对青蛙骨骼肌纤维细胞内 pH 值的影响。
DOI：
10.1152/ajpcell.1985.248.3.c330
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Putnam,RW
中科院分区：
文献类型：
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作者：
Putnam,RW
使用凹尖 pH 敏感玻璃微电极和传统 3 M KCl 填充微电极，研究了胰岛素对青蛙半腱肌纤维细胞内 pH (pHi) 和膜电位的影响。大约 20 分钟的滞后期后，胰岛素 [1 mU/ml，0.1% 牛血清白蛋白 (BSA)] 产生 2-5 mV 的缓慢超极化和 0.05-0.10 pH 单位的碱化，这两个过程均在 1 小时内完成，并且在无胰岛素溶液中洗涤 1 小时也不会逆转。在不同的膜电压下检查了胰岛素对 CO2 诱导的酸化 pHi 恢复率的影响。在正常膜电压下，胰岛素（400 mU/ml，无 BSA）略微增加了缓慢的 pHi 恢复（从 0.01 到 0.04 delta pH/h）。在以 15 mM K 去极化至约 -50 mV 的纤维中，胰岛素的恢复率几乎增加了两倍（从 0.05 到 0.13 delta pH/h）。这种胰岛素诱导的恢复被 1 mM 阿米洛利（一种 Na-H 交换抑制剂）消除。因此，15 mM K 中 pHi 恢复的增加代表 Na-H 交换的增加，这可能是由于胰岛素与膜去极化本身或细胞内 Ca 增加之间的相互作用。在以 50 mM K 去极化至约 -25 mV 的纤维中，胰岛素不影响恢复（0.28 delta pH/h）。这种胰岛素效应的缺乏可能是由于纤维肿胀或细胞内 Ca 升高在 -25 和 -50 mV 的时间过程的差异所致。这些结果与 Na-H 交换介导的青蛙肌肉中胰岛素的碱化作用一致。
The effect of insulin on intracellular pH (pHi) and membrane potential was studied in frog semitendinosus muscle fibers, using recessed-tip pH-sensitive glass microelectrodes and conventional 3 M KCl-filled microelectrodes. After a lag period of approximately 20 min, insulin [1 mU/ml, 0.1% bovine serum albumin (BSA)] produced a slow hyperpolarization of 2–5 mV and an alkalinization of 0.05–0.10 pH unit, which were both completed within 1 h and were not reversed by washing in insulin-free solution for 1 h. The effect of insulin on the pHi recovery rate from CO2-induced acidification was examined at various membrane voltages. At normal membrane voltage, insulin (400 mU/ml, no BSA) slightly increased the slow pHi recovery (from 0.01 to 0.04 delta pH/h). In fibers depolarized in 15 mM K to about -50 mV, insulin nearly tripled the recovery rate (from 0.05 to 0.13 delta pH/h). This insulin-induced recovery was abolished by 1 mM amiloride, a Na-H exchange inhibitor. The increased pHi recovery in 15 mM K thus represents an increased Na-H exchange, which may be due to an interaction between insulin and either membrane depolarization, per se, or increased intracellular Ca. In fibers depolarized in 50 mM K to about -25 mV, insulin did not affect recovery (0.28 delta pH/h). This lack of insulin effect might be due to fiber swelling or to the difference in the time course of elevation of intracellular Ca at -25 and -50 mV. These results are consistent with an alkalinizing effect of insulin in frog muscle mediated by Na-H exchange.