Abstract: | The effects of glucose on phosphorylase and glycogen synthase were investigated in hepatocytes isolated from acutely (40 h) and chronically (90 h) alloxan-diabetic rats. The glucose-induced inactivation of phosphorylase proceeded normally in all conditions. The ensuing activation of glycogen synthase was slightly blunted in acute diabetes, but became virtually absent in 72 h diabetes of similar severity. In hepatocytes from rats with various degrees of chronic diabetes, the maximal activation of glycogen synthase (at 60 mM-glucose) was inversely correlated with the plasma glucose concentration. |