Intracellular content of thiol compounds, thiobarbituric acid reactive substances and gamma-glutamyl transpeptidase in rat brain during anoxia.

Intracellular thiol compounds like glutathione play an important role in scavenging free radicals. Free radical reactions occur in the respiratory chain, and free radicals are known to accumulate in hypoxia and ischaemia. The content of thiobarbituric acid (TBA) reactive substances, thiol and non-protein thiol (reduced glutathione) concentrations along with the activity of gamma-glutamyl transpeptidase (GGTP), a membrane enzyme, were estimated in three regions of the brain in rats exposed to anoxia. It was observed that no change occurred in the content of TBA-reactive substances in any one of the three brain regions, although a significant increase in the non-protein thiol concentration occurred uniformly during anoxia. A significant increase in GGTP occurred in all the three brain regions during anoxia. The increase in the activity of GGTP is suggestive of an alteration in the function of blood-brain barrier during anoxia. These results are suggestive of an absence of lipid peroxidative damage during anoxia.