title: Free radical involvement in the oxidative phenomena induced by tert-butyl hydroperoxide in erythrocytes.
abstract: Free radical involvement in the oxidative events induced by tert-butyl hydroperoxide in erythrocytes has been demonstrated by the use of the electron spin resonance technique of spin trapping with the spin trap 5.5-dimethyl-1-pyrroline-N-oxide (DMPO). The reactions of tert-butyl hydroperoxide with haemoglobins and intact cell systems were studied. Oxyhaemoglobin-containing system showed exclusive production of the t-butyloxy radical spin adduct of DMPO (DMPO-OBut), indicating t-butyloxy radical production. Methaemoglobin-containing systems showed the production of an oxidised derivative of DMPO, 5,5-dimethyl-2-ketopyrrolidino-1-oxyl (DMPOX)-previously associated with the generation of highly oxidised haem-iron. Carbon monoxyhaemoglobin-containing systems show the production of both DMPO-OBut and DMPOX but markedly slower than in either of the other haemoglobin systems. Generally, free radical production in haemoglobin systems was faster than in intact cell systems, indicating a membrane transport rate-limiting step for the tert-butyl hydroperoxide-mediated effects. Data from the use of free radical scavengers to inhibit DMPO-OBut production was consistent with the known reactivities of the scavengers toward t-butyloxy radicals. These and previously reported results (Trotta, R. J., Sullivan, S. G. and Stern, A. (1981) Biochim. Biophys. Acta 679, 230-237 and (1982) Biochem. J. 204, 405-415) implicate important roles for t-butyloxy radicals and haem intermediates in tert-butyl hydroperoxide-induced lipid peroxidation and haemoglobin oxidation in erythrocytes, respectively.
mesh_terms: D003497:Cyclic N-Oxides / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D004912:Erythrocytes / Q000187:drug effects*; D005609:Free Radicals; D006801:Humans; D010545:Peroxides / Q000494:pharmacology*; D020122:tert-Butylhydroperoxide
chemical_list: D003497:Cyclic N-Oxides; D005609:Free Radicals; D010545:Peroxides; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D020122:tert-Butylhydroperoxide