Glutathione level in melanoma cells and tissue.

We studied the effects of hyperthermia by measuring the content of reduced (GSH) and oxidized (GSSG) glutathione separately in two human melanoma cell lines (MeWo, Be 11) and the xenografts of the same melanomas on nu+/nu+ mice. The Be 11 cell lines are less radiosensitive but more thermosensitive than MeWo cells. Therefore the levels of glutathione were also studied in Be 11 cells after combined treatment with 3.7 Gy plus 42 degrees C for 3 h. The levels of GSH were lower in both untreated MeWo cells and MeWo tumour than in Be 11 cells and Be 11 xenograft. After heating the cells in vitro at 42 degrees C for 3 h and the tumour for 30 min at 43 degrees C the levels of GSH and of GSSG increased in both melanoma cell lines. In the MeWo and Be 11 tumours hyperthermia did not markedly influence GSH levels but the GSSG levels decreased. From these data it followed that the ratios of GSH to GSSG were decreased in both cell lines, whereas the ratios increased in both tumours. X-irradiation had no significant effects on GSH level in Be 11 cell lines, but the content of GSSG increased markedly after combined treatment.