Glutathione status in constituted physiological fluids containing albumin

Abstract

1. 1. Glutathione (GSH) and cysteine, added to the constituted incubation medium, rapidly disappeared from the medium in the presence of bovine serum albumin (BSA). The major portions of added GSH and cysteine were oxidized. Only a fraction was recovered as cysteine-GSH mixed disulfide in case of GSH. About 15–30% cysteine or GSH were not recovered in the media. 2. 2. The rate of GSH oxidation was linear with time, however, GSH disappearance was not linear with GSH concentrations. 3. 3. Oxidation of GSH to GSSG in the albumin supplemented media was greater under O 2 atmosphere, but was significantly decreased under N 2 atmosphere. 4. 4. Catalase, a peroxy radical scavenger, but not dimethyl pyroline N-oxide (DMPO), N-tertbutyl-2(-2 sulfophenyl)-nitrone (NTBSPN), mannitol or Superoxide dismutase (SOD), decreased BSA mediated GSH oxidation. 5. 5. GSH oxidation was abolished when mono- or divalent metal ions were absent in the BSA supplemented media. 6. 6. Alkaline pH favored and acidic pH inhibited GSH oxidation. GSH oxidation was maximum above pH 7.4. GSH oxidation was minimal in the media containing boiled BSA. 7. 7. A reaction mechanism involving the mixed GSH-BSA disulfide formation, followed by the reduction of these disulfides by GSH and subsequent release of GSSG is proposed.