Modulation of glyceraldehyde 3-phosphate dehydrogenase activity in isolated pancreatic islets.
Modulation of glyceraldehyde 3-phosphate dehydrogenase activity in isolated pancreatic islets.
复制标题
离体胰岛中甘油醛 3-磷酸脱氢酶活性的调节。
DOI：
10.1016/0006-2952(96)00391-7
复制
发表时间：
1996
影响因子：
5.8
通讯作者：
Laychock,SG
中科院分区：
文献类型：
--
作者：
Laychock,SG
在5.5或11 mM葡萄糖培养分离的大鼠胰岛长达6天，与新鲜分离的胰岛G3 PD活性相比，胰岛匀浆的甘油醛3-磷酸脱氢酶（G3 PD）活性随时间显著增加。此外，在11 mM葡萄糖下培养胰岛6天后，与在5.5 mM葡萄糖下培养的胰岛的酶活性相比，G3 PD活性显著增加。培养的胰岛在5.5 mM葡萄糖2天的存在下，毛喉素，3-异丁基甲基黄嘌呤（IBMX），和8-溴环AMP也显着增加G3 PD活性与对照胰岛相比，虽然有没有变化，酶活性后，只有1天的培养与毛喉素。用forskolin治疗与G3 PD的Vmax增加相关，但没有观察到NAD的表观Km变化。IBMX和8-溴环AMP也增加了在11 mM葡萄糖培养2天的胰岛中的G3 PD活性。8-溴环AMP不影响或抑制G3 PD活性时，直接加入胰岛匀浆。在5.5或11 mM葡萄糖下用8-溴环GMP培养2天的胰岛未显示G3 PD活性的变化。G3 PD活性的增加与胰岛葡萄糖利用率的显著变化无关。因此，在培养的胰岛中，葡萄糖刺激的持续时间调节G3 PD活性，并且环AMP可以介导胰岛细胞中G3 PD活性的变化。
Culture of isolated rat islets at either 5.5 or 11 mM glucose for up to 6 days was associated with significant time-dependent increases in glyceraldehyde 3-phosphate dehydrogenase (G3PD) activity of islet homogenates compared with freshly isolated islet G3PD activity. In addition, after 6 days of culture of islets at 11 mM glucose, there was a significant increase in G3PD activity compared with the enzyme activity of islets cultured at 5.5 mM glucose. Culture of islets at 5.5 mM glucose for 2 days in the presence of forskolin, 3-isobutylmethylxanthine (IBMX), and 8-bromo-cyclic AMP also significantly increased G3PD activity compared with control islets, although there was no change in enzyme activity after only 1 day of culture with forskolin. Treatment with forskolin was associated with an increase in the Vmaxof G3PD, but no change was observed in the apparent Kmwith NAD. IBMX and 8-bromo-cyclic AMP also increased G3PD activity in islets cultured at 11 mM glucose for 2 days. 8-Bromo-cyclic AMP did not affect or inhibit G3PD activity when added directly to islet homogenates. Islets cultured with 8-bromo-cyclic GMP for 2 days at 5.5 or 11 mM glucose did not show changes in G3PD activity. Increases in G3PD activity did not correlate with significant changes in islet glucose utilization. Thus, G3PD activity is modulated by the duration of glucose stimulation in cultured islets, and cyclic AMP may mediate changes in G3PD activity in islet cells.