[Rat brain and liver glutamine synthetase and gamma-glutamyltransferase activity in alloxan diabetes (IV)].

Glutamine synthetase and gamma-glutamyltransferase activities of brain and liver homogenates of rats suffering from alloxan diabetes were determined in the soluble fraction (fraction 1) and in that obtained after treatment with 0.2 percent deoxycholate (fraction 2). The results obtained indicate that the activities of these enzymes in homogenates of brain and liver of diabetic animals does not differ from that of normal animals. gamma-Glutamyltransferase activity of brain is significantly reduced (about 5 fold) in the soluble fraction while glutamine synthetase activity is not much changed. The activities of glutamine-synthetase and gamma-glutamyltransferase of the 2-nd fraction obtained from rat brain and liver are very much higher than in the first fraction and are not considerably different from the activities observed in normal animals. In contrast to brain, glutamine synthetase and gamma-glutamyltransferase activities of liver of diabetic animals do not differ from the activities observed in normal animals, both in the homogenates and in the 1-st and 2-nd fractions.