[Enzyme activity and substrate levels of the Krebs cycle in the brain tissue of rats with insulin-induced hypoglycemia and during the recovery period].

Alterations in enzymatic activity and in content of substrates involved in the Krebs cycle and in content of glutamate were studied in brain of rats with insulin-dependent coma and in various periods of the coma restoration with glucose. After administration of glucose content of the Krebs cycle substrates and succinate dehydrogenase activity, which were lowered during the coma, were not normalized, whereas the content of glutamate and activity of cytoplasmic NAD-dependent malate dehydrogenase were increased in brain. Functional impairments of the nervous system in hypoglycemia and the restoration effect of glucose appear to involve some alterations in glutamate metabolism in brain.