Tamagawa T, Iguchi A, Uemura K, Miura H, Nonogaki K, Ishiguro T, Sakamoto N
Third Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Endocrinol Jpn. 1992 Jun;39(3):325-9. doi: 10.1507/endocrj1954.39.325.
The role of protein phosphatases in the regulation of insulin release from rat pancreatic islets was studied with protein phosphatase inhibitors, okadaic acid and calyculin A. Okadaic acid inhibited glucose- and glyceraldehyde-induced insulin release dose-dependently and also inhibited the potentiation of glucose-induced release either by adding forskolin, an activator of adenylate cyclase or by increasing K+ concentration to 25 mM. At a non-stimulatory concentration of 3 mM glucose, a high concentration (2 microM) of okadaic acid inhibited insulin release induced by high K+ or 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, but a low concentration (1 microM) of okadaic acid did not significantly inhibit TPA-induced insulin release. Calyculin A also inhibited glucose-induced insulin release, and the effect was greater than that of okadaic acid. The data suggest that protein phosphatases may play an important role in the regulation of insulin release.
利用蛋白磷酸酶抑制剂冈田酸和花萼海绵诱癌素A研究了蛋白磷酸酶在调节大鼠胰岛胰岛素释放中的作用。冈田酸剂量依赖性地抑制葡萄糖和甘油醛诱导的胰岛素释放，并且还抑制通过添加腺苷酸环化酶激活剂福斯可林或通过将钾离子浓度增加到25 mM来增强葡萄糖诱导的释放。在3 mM葡萄糖的非刺激浓度下，高浓度（2 μM）的冈田酸抑制高钾或蛋白激酶C激活剂12-O-十四酰佛波醇-13-乙酸酯（TPA）诱导的胰岛素释放，但低浓度（1 μM）的冈田酸并未显著抑制TPA诱导的胰岛素释放。花萼海绵诱癌素A也抑制葡萄糖诱导的胰岛素释放，且其作用大于冈田酸。数据表明蛋白磷酸酶可能在胰岛素释放的调节中起重要作用。
