title: Oxygen concentration and the OER for acutely or chronically thiol deficient cells.
abstract: Glutathione (GSH) is one of several intracellular hydrogen donating species thought to compete with O2, a damaging species, to repair radiation induced free radical damage. The O2 K factor was determined for normal Chinese hamster V79 cells, V79 cells made acutely thiol deficient (no detectable GSH or NPSH) using the gamma-glutamyl-cysteine synthetase enzyme inhibitor D,L-Buthionine-S,R-sulfoximine (D,L-BSO), or a human skin fibroblast cell line GM3877 which, because of the nature of its genetic defect, has chronically low levels of GSH (7% of normal skin fibroblasts). The K factors for normal V79 cells, treated with BSO or GSH deficient human fibroblasts, were 0.54, 0.15, and 0.1% O2, respectively. While thiol depletion affects the O2 K factor, V79 cells without any detectable GSH were still not as sensitive as the genetically deficient line GM3877 with 7% of normal GSH values. Other factors which may influence the results are whether the GSH levels remain low or regenerate following irradiation and the intracellular distribution of GSH.
mesh_terms: D000818:Animals; D019328:Buthionine Sulfoximine; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D006224:Cricetinae; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008717:Methionine Sulfoximine / Q000031:analogs & derivatives / Q000494:pharmacology; D010100:Oxygen / Q000502:physiology*; D011836:Radiation Tolerance
chemical_list: D008717:Methionine Sulfoximine; D019328:Buthionine Sulfoximine; D005978:Glutathione; D010100:Oxygen