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胰岛淀粉样多肽(amylin)使高糖和胰岛素刺激引起的肝细胞糖原累积速率明显降低,也使刺激24小时后的肝细胞糖原含量明显降低。培养基中游离葡萄糖浓度测定结果显示,amylin可以诱导肝细胞释放葡萄糖。amylin和胰高血糖素均可很快诱导肝细胞内糖原磷酸化酶a活力的增加。虽然amylin对酶活力诱导作用的高峰出现比胰高血糖素晚,但前者对醇活力诱导增加幅度及诱导作用持续时间却较长。amylin对酶活力的诱导作用具有明显的剂量依赖关系。上述结果提示,amylin可以通过激活糖原磷酸化酶活力,加强小鼠肝细胞的糖原分解过程,促进肝细胞对葡萄糖的释放,从而对肝细胞内糖原储量及糖代谢平衡进行调节。因而amylin这一与胰岛素共存于B细胞,又一同被分泌入血的多肽,可能对维持整体内的糖代谢稳态具有重要意义。
Amyloid amylase significantly reduced glycogen accumulation in hepatocytes caused by high glucose and insulin stimulation and markedly reduced glycogen content in hepatocytes 24 hours after stimulation. The results of free glucose concentration in culture medium showed that amylin could induce the release of glucose in liver cells. Both amylin and glucagon rapidly induce increased glycogen phosphorylase activity in hepatocytes. Although the peak of amylin’s induction of enzyme activity appeared later than that of glucagon, the former increased the extent of induction of alcohol activity and the duration of induction was longer. Amylin on the induction of enzyme activity has a significant dose-dependent relationship. These results suggest that amylin can activate glycogen phosphorylase activity, enhance glycogenolysis in mouse hepatocytes, and promote the release of glucose by hepatocytes, so as to regulate glycogen storage and glucose metabolism balance in hepatocytes. Thus, amylin, a polypeptide that coexists with insulin in B cells and is also secreted into the blood, may have important implications for the maintenance of overall glucose homeostasis.