Glutathione content of cultured cells and rodent brain regions: a specific fluorometric assay.

The glutathione contents of cultured cells and rodent brain were determined by a fluorometric procedure which eliminates the interference of endogenous histidine-containing compounds. Cultured neonatal rat and hamster astrocytes, human dermal fibroblasts, and mouse and rat brain regions were assayed. o-Phthalaldehyde forms a fluorescent complex with glutathione, oxidized glutathione, and histidyl compounds in the absence of added thiol. The reaction of histidyl compounds can be abolished by the addition of formaldehyde to the reaction mixtures. A 10-pmol quantity of glutathione can be measured in dilute formic acid extracts of milligram quantities of tissue.