Khandelwal R L, Zinman S M, Zebrowski E J
Biochem J. 1977 Dec 15;168(3):541-8. doi: 10.1042/bj1680541.
The effects of streptozotocin-induced diabetes and of insulin supplementation to diabetic rats on glycogen-metabolizing enzymes in liver were determined. The results were compared with those from control animals. The activities of glycogenolytic enzymes, i.e. phosphorylase (both a and b), phosphorylase kinase and protein kinase (in the presence or in the absence of cyclic AMP), were significantly decreased in the diabetic animals. The enzyme activities were restored to control values by insulin therapy. Glycogen synthase (I-form) activity, similarly decreased in the diabetic animals, was also restored to control values after the administration of insulin. The increase in glycogen synthase(I-form) activity after insulin treatment was associated with a concomitant increase in phosphoprotein phosphatase activity. The increase in phosphatase activity was due to (i) a change in the activity of the enzyme itself and (ii) a decrease in a heat stable protein inhibitor of the phosphatase activity.
测定了链脲佐菌素诱导的糖尿病以及给糖尿病大鼠补充胰岛素对肝脏糖原代谢酶的影响。将结果与对照动物的结果进行了比较。糖尿病动物中糖原分解酶的活性，即磷酸化酶（a型和b型）、磷酸化酶激酶和蛋白激酶（在有或无环磷酸腺苷的情况下）显著降低。通过胰岛素治疗，酶活性恢复到对照值。糖原合酶（I型）活性在糖尿病动物中同样降低，在给予胰岛素后也恢复到对照值。胰岛素治疗后糖原合酶（I型）活性的增加与磷蛋白磷酸酶活性的相应增加相关。磷酸酶活性的增加是由于（i）酶本身活性的变化和（ii）磷酸酶活性的热稳定蛋白抑制剂的减少。
