膵潅流法によるMSG肥満マウスの膵β細胞インスリン動態に関する研究

为探讨谷氨酸诱导的肥胖小鼠（MSG小鼠）高胰岛素血症的发生机制，用10%谷氨酸（MSG）每24小时皮下注射一次，使ICR系雄性小鼠（Jcl）肥胖，持续5天。在4、8、12、24和36周龄时，在空腹和自由进食时测量血糖和血浆胰岛素水平。在8周龄和24周龄时进行葡萄糖耐量试验和精氨酸耐量试验。按照Grodsky等的方法进行胰腺灌注，用30 mM葡萄糖和19 mM精氨酸刺激胰岛素分泌，每隔1分钟测量灌注液中的胰岛素，4周龄时，与对照组小鼠相比，自由进食时MSG小鼠的血浆胰岛素水平略高。12周龄后，在喂食MSG的小鼠中观察到血浆胰岛素水平显著升高。MSG小鼠在8周龄时通过精氨酸耐受试验显示胰岛素分泌显著增加。在胰腺灌注实验中，MSG小鼠对葡萄糖和精氨酸均保持完整的胰岛素反应，提示MSG小鼠的高胰岛素血症可能是由于神经调节功能紊乱所致。

The mechanism of the hyperinsulinemia of the monosodium glutamate-induced obese mice (MSG mice) was investigated.The male mice (Jcl : ICR strain) were rendered obese by subcutaneous injection of 10% monosodium L-glutamate (MSG), 2 mg/g of weight every 24 hour, for the first five postnatal days. Blood glucose and plasma insulin levels were measured at fasting and at feeding ad libitum on 4,8,12,24, and 36 weeks of age. Glucose tolerance tests and arginine tolerance tests were performed at 8 and 24 weeks of age. The pancreas perfusions were performed according to the method of Grodsky et al. The insulin secrition was stimulated with 30 mM glucose and 19 mM arginine, and insulin in the perfusate were measured at an interval of one minute.At 4 weeks of age, plasma insulin level at feeding ad libitum were slightly higher in the MSG mice compared to the control mice. Marked elevation of the plasma insulin level was observed in fed MSG mice after 12 weeks of age. The MSG mice revealed a marked increase in insulin secretion by arginine tolerance test at 8 weeks of age. On the pancreas perfusion study, intact insulin response to both blucose and arginine was maintained in the MSG mice.These results suggest that the hyperinsulinemia of the MSG mice may be caused by the disorder in neurological regulation.