The activities of the enzymes related to glutathione synthesis,
degradation, and functions as well as reactive oxygen scavenging
enzymes were analyzed in different brain regions, such as cerebral
hemisphere, cerebellum, brainstem, thalamus, and hypothalamus
after 1 and 3 mo of streptozotocin-induced diabetes in rats. Parallel
studies were also made in age-matched control rats and insulintreated diabetic rats. The content of glutathione (GSH) and its synthesizing enzyme 7-glutamylcystein synthetase and also superoxide
dismutase (SOD) and catalase activities (reactive oxygen scavenging
enzymes) were significantly decreased from almost all the brain
regions studied. However, glutathione peroxidase (GPx), glutathione
reductase (GR), glutathione S-transferase (GST), 7-glutamyl transpeptidase (7-GTP), and gtutamine synthetase (GS) activities were
increased in the diabetic rat brain. Insulin treatment to the diabetic
rats resulted in partial to full recovery in these enzymes activities. The
present results emphasize the potentially serious alterations of brain
free radical scavenger system in uncontrolled Type I diabetes.