BRAIN GLUTAMATE-DEHYDROGENASE CHANGES IN STREPTOZOTOCIN-DIABETIC RATSAS A FUNCTION OF AGE

Kinetic parameters of brain glutamate dehydrogenase (GDH) were compare d in the brain stem, cerebellum and cerebral cortex of three weeks and one year old streptozotocin (STZ) induced four day diabetic rats with respective controls. A single intrafemoral dose of STZ (60mg/Kg body weight) was administered to induce diabetes in both age groups. After four days the blood glucose levels showed a significant increase in th e diabetic animals of both age groups compared with the respective con trols. The increase in blood glucose was significant in one year old c ompared to the three weeks old diabetic rats. The V-max ofthe enzyme w as decreased in all the brain regions studied, of the three weeks old diabetic rats without any significant change in the K-m. In the adult the V-max of GDH was increased in cerebellum and brain stem but was un changed in the cerebral cortex. The K-m was unchanged in cerebellum an d cerebral cortex but was increased in the brain stem. These results s uggest there may be an important regulatory role of the glutamate path way in brain neural network disturbances and neuronal degeneration in diabetes as a function of age.