Analysis of the intracellular signal pathway in the pancreatic b-cells by direct observation of exocytosis

本研究的目的是阐明主要自由基物种对胰腺β细胞胰岛素释放的参与。为此，我们在胰岛细胞上施用NO、O_<2”>和α -生育酚。这些自由基诱导β细胞脱颗粒。我们还观察了含MCLA的培养液灌注胰腺组织后的化学发光现象。葡萄糖对组织的刺激显著增加了mcla依赖的化学发光，特别是在胰岛附近。因此，我们得出结论，葡萄糖浓度的升高导致组织中自由基的产生，自由基诱导β细胞的脱颗粒。α -生育酚也能在同一组织中诱导脱颗粒。α -生育酚的这种作用被某些类型的牛血清白蛋白阻断。本研究表明自由基不仅对β细胞有不良影响，而且在导致胰岛素释放的信号通路中具有重要的生理作用。还应强调的是，β细胞对自由基具有特殊的敏感性，一些自由基清除剂在b细胞中充当自由基物种。

The purpose of the present study is to clarify the involvement of major radical species on the insulin release from the pancreatic beta-cells. To this end, we applied NO,O_<2">, and alpha-tochopherol on the islet cells. These radicals induced degranulation of the beta-cells. We also observed chemiluminescene in the pancreatic tissue in vivo perfused with MCLA containing medium. Stimulation of the tissue with glucose significantly increased the MCLA-dependent chemiluminescence especially in the vicinity of the islet. Therefore, it was concluded that elevation in the glucose concentration results in radical production in the tissue and radicals induces degranulation in the beta-cells. alpha-tocopherol also induced degranulation in the same tissue. This effect of alpha-tocopherol was blocked by some types of bovine serum albumin. The present study clarified that radicals have not only adverse effects on the beta-cell but also physiologically important role in signal pathway leading to insulin release. It should be also emphasized that the beta-cells has a special sensitivity to radicals, and some radical scavengers act as radical species in the b-cells,