The influence of cold restraint stress on some components of the antioxidant defence system in the tissues of rats of various ages.

Rats of various ages were subjected to stress by confinement in restraining cages at 2-4 degrees C. Analysis of the plasma of these animals revealed an elevation in corticosteroids of approximately 50% above the control level. The livers of all the groups of cold-restrained animals contained significantly more lipoperoxide (estimated as thiobarbituric-acid-reactive material) than did control hepatic tissue. The plasma of the 12-, 24-, and 32-wk-old groups of rats subjected to stressful treatment also contained significantly higher lipoperoxide levels. There was no significant difference between the lipoperoxide levels of the brain tissue of control or stress-treated rats. The activities of both glutathione peroxidase and glutathione reductase were increased in hepatic, but not brain, tissue of the stressed animals. The perturbation of the activities of these enzymes did not produce any significant change in the ratio of reduced, oxidized glutathione. The livers of the stressed animals had significantly less total glutathione than those of the controls.