Effect of high altitude (7,620 m) exposure on glutathione and related metabolism in rats

Reduced and oxidised glutathione (GSH and GSSG) contents, and glutathione reductase, and glutathione S-transferase activities were studied in the livers, muscles, and blood/erythrocytes of male Sprague-Dawley rats exposed to intermittent hypoxia (6 h (.) day(-1)) at a simulated altitude of 7,620 m for 1, 7, 14, and 31 days. Significant decreases in GSH and increases in GSSG contents were observed in the muscles and blood of hypoxia-exposed rats in comparison to unexposed rats. Significant declines in GSH content by 43% and 45% respectively in muscles and blood were observed in the group exposed for 1 day which tended to recover on subsequent exposure. Glutathione reductase and glutathione S-transferase activities were decreased in the livers and erythrocytes of hypoxia-exposed rats, but were increased significantly in muscle. Lipid peroxidation was also increased in the livers and muscles of exposed rats. The changes were indicative of an increased production of reactive oxygen species and an impairment of drug and xenobiotic metabolism during exposure to high altitude hypoxia.