Metabolism of glutathione in tumour cells as evidenced by 1H MRS

1H MRS signals of glutathione and of free glutamate were examined in samples from cultured tumour cells, namely MCF-7 from mammary carcinoma and TG98 from malignant glioma, with the aim of relating signal intensities to aspects of GSH metabolism. Spectra of cells harvested at different cell densities suggest that GSH and glu signal intensities are related to cell density and proliferation and their ratio is dependent on the activity of the γ-glutamyl cysteine synthetase. The hypothesis is confirmed by experiments performed on cells treated with buthionine sulfoximine that inhibits the enzyme activity.