Quantitative analysis of glutathione in human brain tumors

Abstract

✓ Reduced glutathione (γ-glutamylcysteinylglycine, GSH) plays an important role in the protection of cells against damage from free radicals and other electrophils and also influences cellular radiosensitivity, cellular response to hyperthermia, and cytotoxicity to some kinds of chemotherapeutic agents. The concentrations of GSH in 40 primary and metastatic brain tumors were quantitatively analyzed, and GSH was localized in these tumors by a novel o-phthalaldehyde histofluorescence method. The level of GSH was 195.2 ± 57.1 µg/gm (mean ± standard deviation) in glioblastomas multiforme, 444.1 ± 105.1 µg/gm in normal brain tissues, and 614.4 ± 237.4 µg/gm in meningiomas. The differences in GSH levels between glioblastomas and normal brain tissues and between glioblastomas and meningiomas were statistically significant (p < 0.01). The mean GSH level in astrocytoma grades II and III was 321.9 ± 11.8 µg/gm. The difference in the GSH level between glioblastomas and astrocytomas was statistically significant (p < 0.05). Radiosensitive tumors, such as multiple myeloma, germinoma, and small-cell carcinoma, showed low GSH levels. These data suggest the possibility that the GSH may be a predictor for the efficacy of radiation therapy. The cytochemical study showed GSH localized in the cytoplasm; although it stained well in meningioma tissue, GSH was not well stained in sections of multiple myeloma. The endothelial proliferation did not stain well in glioblastoma, which seems to imply that this area is vulnerable to attack by free radicals from irradiation and/or chemotherapy.