Immobilization stress-induced antioxidant defense changes in rat plasma: effect of treatment with reduced glutathione.

1. We examined immobilization stress-induced antioxidant defense changes in rat plasma and observed the antioxidant effect of reduced glutathione (GSH) administration on these changes. 2. Immobilization stress induced severe bleeding in the stomach and a significant increase in plasma levels of thiobarbituric acid receives substances (TBARS). 3. Immobilization stress induced a significant decrease in plasma iron-binding, iron-oxidizing protections and radical scavenging activity. 4. Plasma levels of ascorbic acid, ascorbyl radical and superoxide dismutase activity remained unchanged following immobilization stress. 5. Treatment with GSH showed a significant protective effect on stomach bleeding, on the increase in plasma TBARS, and on the decrease of iron-binding, iron-oxidizing protection and radical scavenging activity in plasma. 6. These results suggest that immobilization stress induces generation of reactive oxygen species and decreases the endogenous antioxidant defenses, which can be attenuated by extracellular administration of antioxidant GSH.