Salehi A, Parandeh F, Lundquist I
Department of Pharmacology, University of Lund, Sweden.
Biosci Rep. 1998 Feb;18(1):19-28. doi: 10.1023/a:1022288600348.
The nature of the action of the nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on hormone release from isolated islets was investigated. We found that glucose-induced insulin release was potentiated by L-NAME in the absence or presence of diazoxide, a potent K+ATP channel opener, as well as in the presence of diazoxide plus a depolarizing concentration of K+. At a low, physiological glucose concentration L-NAME did not influence insulin secretion induced by K+ but inhibited glucagon secretion. L-arginine-induced insulin release was potentiated by L-NAME. This potentiation was observed also in the presence of K+ plus diazoxide. Further, glucagon release induced by L-arginine as well as by L-arginine plus K+ and diazoxide was suppressed by L-NAME. The results strongly suggest that the L-NAME-induced potentiation of insulin secretion in response to glucose or L-arginine as well as the inhibitory effects on glucagon secretion are largely mediated by L-NAME directly suppressing islet NOS activity. Hence NO apparently affects insulin and glucagon secretion independently of membrane depolarization events.
研究了一氧化氮合酶（NOS）抑制剂NG-硝基-L-精氨酸甲酯（L-NAME）对分离胰岛激素释放的作用性质。我们发现，在不存在或存在二氮嗪（一种有效的K +ATP通道开放剂）的情况下，以及在存在二氮嗪加去极化浓度的K +的情况下，L-NAME均可增强葡萄糖诱导的胰岛素释放。在低生理葡萄糖浓度下，L-NAME不影响K +诱导的胰岛素分泌，但抑制胰高血糖素分泌。L-精氨酸诱导的胰岛素释放被L-NAME增强。在存在K +加二氮嗪的情况下也观察到这种增强作用。此外，L-NAME抑制了L-精氨酸以及L-精氨酸加K +和二氮嗪诱导的胰高血糖素释放。结果强烈表明，L-NAME诱导的对葡萄糖或L-精氨酸的胰岛素分泌增强以及对胰高血糖素分泌的抑制作用在很大程度上是由L-NAME直接抑制胰岛NOS活性介导的。因此，NO显然独立于膜去极化事件影响胰岛素和胰高血糖素的分泌。
