Roles of selenium and sulfur-containing amino acids in protection against oxygen toxicity.

摘要: Tolerance and adaptation to hyperoxia have been correlated with increases in antioxidant enzymes. This study evaluated whether selenium deficiency would prevent an increase glutathione peroxidase (GSHPX), a selenium-containing enzyme, during oxygen exposure, and, thus, inhibit adaptation. Because the Torula yeast-based diet, which was used produce deficiency, also deficient cysteine methionine, effects of these deficiencies were evaluated. When rats exposed 80% for 1 week, mortality both sulfur-containing amino acids, 40% selenium-deficient rats, 35% cysteine- methionine-deficient 0% fed either standard laboratory diet or selenium, cysteine-, methionine-supplemented yeast diet. However, only one six surviving low none from any other dietary group died subsequent 96 hours 98% oxygen, indicating (LD50 unadapted is 72 hours.) GSHPX activity (per gram dry weight) decreased 85% lungs unexposed diets. After lung elevated all groups. Rats high diets had 47% enzyme activity, whereas 214% increase. Although caused relatively percentage Se resulting absolute 34 70% that rats. The results indicate acids contribute defense. although stress hyperoxic exposure produces better tolerance than hyperoxia.