Substrate requirements for the phosphoinositide response in rat pancreatic islets.
Substrate requirements for the phosphoinositide response in rat pancreatic islets.
复制标题
大鼠胰岛中磷酸肌醇反应的底物要求。
DOI：
10.1016/0304-4165(81)90340-8
复制
发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Pace,CS
中科院分区：
文献类型：
--
作者：
ClementsJr,RS;Evans,MH;Pace,CS
本文用肌醇标记的大鼠胰岛细胞暴露于不同的胰岛素分泌激动剂和拮抗剂中，研究了肌醇磷脂水解与胰岛素分泌第一时相的关系。随着孵育培养基中d-葡萄糖浓度的增加，脂质结合放射性的回收率逐渐降低。那些刺激胰岛素分泌的碳水化合物引起磷酸肌醇反应，而非刺激性碳水化合物没有。除氨基酸外，还发现非碳水化合物促分泌素可降低胰岛脂质结合放射性。发现抑制胰岛葡萄糖代谢可降低脂质结合放射性的回收率，这主要是由于磷酸肌醇从头合成受损。磷酸肌醇对葡萄糖的反应不受微管功能抑制的影响，但依赖于细胞外钙离子的可用性。我们的结论是，在碳水化合物刺激的胰岛中的phopshoinoditide响应是不直接相关的膜相关的葡萄糖受体的激活，但可能会发生作为一个后果，随后的跨膜运动的钙离子。最后，观察到刺激性氨基酸没有引起磷酸肌醇反应表明，在某些情况下，这种现象可以从胰岛素分泌分离。
The relationship between phopshatidylinositol hydrolysis and the first phase of insulin secretion has been investigated by briefly exposing rat pancreatic islets that had been prelabelled withmyo-[2-3H]inositol to various agonists and antagonist of insulin secretion. The recovery of lipid-bound radioactivity progressively decreased as thed-glucose concentration of the incubation medium was increased. Those carbohydrates that stimulated insulin secretion evoked a phopshoinositide response, whereas non-stimulatory carbohydrates did not. With the notable exception of amino acids, non-carbohydrate secretagogues were also found to decrease the islet lipid-bound radioactivity. Inhibition of islet glucose metabolism was found to decrease the recovery of lipid-bound radioactivity, largely as a result of impairedde novo phospshoinositide synthesis. The phospshoinositide response to glucose was not affected by inhibition of microtubular function, but was dependent upon the availability of extracelular calcium ions. We conclude that the phopshoinoditide response in carbohydrate-stimulated islets is not directly related to the activation of membrane-associated glucose receptors, but may occur as a consequence of the subsequent transmembrane movement of calcium ions. Finally, the observation that stimulatory amino acids did not evoke a phopshoinositide response suggests that, under certain circumstances, this phenomenon can be dissociated from insulin secretion.