Burchell A, Cain D I
Diabetologia. 1985 Nov;28(11):852-6. doi: 10.1007/BF00291077.
Hepatic microsomal glucose-6-phosphatase activity levels and the hepatic output of glucose are increased in diabetes. We have used protein chemistry and immunological techniques to determine the mechanism by which the activity levels of the glucose-6-phosphatase system are increased in streptozotocin-induced diabetic rats. In the streptozotocin-induced diabetic rats, the activity of the glucose-6-phosphatase enzyme increased four-fold without appreciably altering the transport capacity of the glucose-6-phosphatase system. The solubilized diabetic rat liver glucose-6-phosphatase enzyme appeared to be very similar to the solubilized enzyme from control rat liver microsomes. They exhibit the same Km, are labile at 30 degrees C, are stabilized by sodium fluoride and they migrate to the same position during density gradient centrifugation. Immunological studies demonstrated that a greater amount of hepatic microsomal glucose-6-phosphatase enzyme protein is present in diabetic rats than in control rats. Thus, we have determined for the first time that increased levels of the glucose-6-phosphatase protein are present in streptozotocin-induced diabetes. The significance of this finding in relation to the regulation of the hepatic microsomal glucose-6-phosphatase system is discussed.
糖尿病时肝脏微粒体葡萄糖-6-磷酸酶活性水平及肝脏葡萄糖输出增加。我们运用蛋白质化学和免疫学技术来确定链脲佐菌素诱导的糖尿病大鼠中葡萄糖-6-磷酸酶系统活性水平升高的机制。在链脲佐菌素诱导的糖尿病大鼠中，葡萄糖-6-磷酸酶的活性增加了四倍，而葡萄糖-6-磷酸酶系统的转运能力没有明显改变。溶解的糖尿病大鼠肝脏葡萄糖-6-磷酸酶似乎与对照大鼠肝脏微粒体中的溶解酶非常相似。它们具有相同的米氏常数，在30℃时不稳定，可被氟化钠稳定，并且在密度梯度离心过程中迁移到相同位置。免疫学研究表明，糖尿病大鼠肝脏微粒体中葡萄糖-6-磷酸酶蛋白的含量高于对照大鼠。因此，我们首次确定链脲佐菌素诱导的糖尿病中葡萄糖-6-磷酸酶蛋白水平升高。讨论了这一发现与肝脏微粒体葡萄糖-6-磷酸酶系统调节的关系。
