Zaitsev S V, Efendić S, Arkhammar P, Bertorello A M, Berggren P O
Rolf Luft Center for Diabetes Research, Department of Molecular Medicine, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden.
Proc Natl Acad Sci U S A. 1995 Oct 10;92(21):9712-6. doi: 10.1073/pnas.92.21.9712.
Simultaneous measurements of cytosolic free Ca2+ concentration and insulin release, in mouse single pancreatic islets, revealed a direct correlation only initially after stimulation with glucose or K+. Later, there is an apparent dissociation between these two parameters, with translocation of alpha and epsilon isoenzymes of protein kinase C to membranes and simultaneous desensitization of insulin release in response to glucose. Recovery of insulin release, without any concomitant changes in cytosolic free Ca2+ concentration, after addition of phorbol 12-myristate 13-acetate, okadaic acid, and forskolin supports the notion that the desensitization process is accounted for by dephosphorylation of key regulatory sites of the insulin exocytotic machinery.
在小鼠单个胰岛中同时测量胞质游离钙离子浓度和胰岛素释放，结果显示，仅在葡萄糖或钾离子刺激后最初阶段二者存在直接相关性。之后，这两个参数之间出现明显分离，蛋白激酶C的α和ε同工酶转位至细胞膜，同时胰岛素释放对葡萄糖的反应出现脱敏现象。添加佛波醇12-肉豆蔻酸酯13-乙酸酯、冈田酸和福斯高林后，胰岛素释放恢复，而胞质游离钙离子浓度未伴随任何变化，这支持了以下观点：脱敏过程是由胰岛素胞吐机制关键调节位点的去磷酸化引起的。
