Variable alpha-tocopherol stimulation and protection of glutathione peroxidase activity in non-transformed and transformed fibroblasts.

ABSTRACT

Studies on glutathione metabolism in an established baby hamster kidney cell line (BHK-21/C13) and in its polyoma virus-transformed counterpart (BHK-21/PyY), have revealed a significant stimulation of intracellular glutathione peroxidase activity (Se-independent plus Se-dependent) by alpha-tocopherol supplementation (14 microM). This stimulation was found to be much greater in the transformed cells. Other GSH-requiring enzyme activities (namely glutathione reductase and glutathione transferase) were unaltered by alpha-tocopherol treatment, suggesting a degree of specificity in its action on GSHpx. In unsupplemented growth media, the GSHpx activity in both cell lines was significantly decreased by an oxidative stress. However, the same stress applied to the alpha-tocopherol-supplemented cells had no effect on the stimulated GSHpx activity, suggesting a protection afforded by the alpha-tocopherol.