Effects of ammonia intoxication and liver injury on rat brain glutamate-dehydrogenase and glutaminase activity.

Glutamate dehydrogenase (GDH) and glutaminase activity in the rat brain was altered by chronic ammonia intoxication, subacute liver injury induced by CCl4 or digalactosamine, and the combination of them. GDH activity was found to increase considerably in ammonia intoxication without liver damage, probably as a result of enzyme induction. GDH activity failed to increase, while glutaminase was appreciably elevated. when ammonia intoxication was associated with hepatic injury. Toxicological studies have indicated that these changes in brain enzyme levels may be involved in the mechanism of ammonia neurotoxicity.