Characterization and localization of glutathione-S-transferases in rat brain and binding of hormones, neurotransmitters, and drugs.

Rat brain glutathione-S-transferases are rich in Yb type subunits with major RNA transcripts coding for a relatively uncommon Yb3 form. The Yb-containing isoenzymes of brain cytosol bind glucocorticoids and are covalently labeled with dexamethasone 21-methanesulfonate. Certain neurotransmitters, hormones, and drugs, such as serotonin, dopamine, glucocorticoids, thyroxine, apomorphine, and benzodiazepine derivatives, are effective inhibitors of brain glutathione transferase activity. Immunocytochemical studies show that Yb forms are localized in ependymal cells, subventricular zone cells, astrocytes, tanycytes, and astrocyte foot processes on blood vessels, but Yb was not detected in oligodendrocytes or neurons. Based on their localization and binding properties, brain glutathione-S-transferases have the potential to function in intracellular binding of a variety of compounds and thereby govern their uptake and release in brain, transport to neurons, as well as in their detoxification.