Accurate measurement of oxidized glutathione content of human, rabbit, and rat red blood cells and tissues

1. 1. A method for the accurate measurement of oxidized glutathione (GSSG) in the erythrocytes and body tissues has been described. The oxidation of reduced glutathione to GSSG during protein precipitation by trichloroacetic acid is prevented by prior alkylation of the sulfhydryl groups with N-ethylmaleimide (NEM). Trichloroacetic acid and excess NEM are extracted with ether. The GSSG in the extract is measured enzymically using glutathione oxidoreductase. 2. 2. Oxidized glutathione content (average ± standard deviation) of human, rabbit, and rat erythrocytes has been shown to be 3.6 ± 1.4, 5.6 ± 0.7 and 6.1 ± 2.6 mμmoles/ml RBC, respectively. 3. 3. The GSSG content of rat liver, kidney, heart, lens, testes, and skeletal muscles is below the level of detection, i.e., 0.03 μmole/gm tissue.