Some Aspects of Glutathione Metabolism in Ataxia-telangiectasia Fibroblasts

Summary

Levels of glutathione (GSH) and two enzymes involved in GSH metabolism, glutathione reductase (GR) and glutathione-S-transferase(s) (GST), were measured in four SV40-transformed human fibroblast cell lines. MRC5-V1 and GM0637, derived from normal individuals, had mean GSH levels of 4·2 and 6·5 nmoles/10⁶ cells, respectively. TAT2SF and AT5BIVA, both from ataxiatelangiectasia (A-T) patients, respectively had 6·5 and 4·2 nmol/10⁶ cells, indicating that basal GSH levels were similar in A-T and normal cells. There was some variation in GST activity among the four cell lines but deficiency in this enzyme cannot be associated with radiosensitivity in A-T. When GR activity was measured, A-T cells had approximately 82 per cent of the mean normal activity. Though statistically significant, (P = 0·05), this small deficiency could be due to chance and is unlikely to be responsible for the radiosensitive phenotype of A-T.