Glutathione (GSH) b performs a variety of important physiological and metabolic functions in all mammalian cells, including the detoxification of free radicals, metals, and other electrophilic compounds. One important detoxification mechanism involves the binding of GSH to electrophilic chemicals and the export of the resulting GSH S-conjugates from the cell. These conjugation reactions have been extensively characterized for a multitude of foreign chemicals, but they are also critical for the metabolism of endogenous reactive intermediates and for the formation of specific biological mediators. GSH forms thioether conjugates with leukotrienes, pros-a Address for correspondence: Ned Ballatori, Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642. E-mail: Ballatorin@ envmed. rochester. edu. b Abbreviations:-MeDA,-methyldopamine; GT,-glutamyl transpeptidase; ATP, adenosine triphosphate; CoASSG, GSH-coenzyme A mixed disulfide; DCE-SG, S-(12-Dicarboxyethyl) glutathione; DNA, deoxyribonucleic acid; EDRF, endothelium-derived relaxing factor; GS-NO, S-nitrosoglutathione; GSH, reduced glutathione; GspdSH, N1-monoglutathionylspermidine; GSSG, glutathione disulfide; HHE, 4-hydroxyhexenal; HNE, 4-hydroxynonenal; LTA4, leukotriene A4; LTB4, leukotriene B4; LTC4, leukotriene C4; LTD4, leukotriene D4; LTE4, leukotriene E4; MDA, 34-()-(methylenedioxy) amphetamine; MeDA-SG, 5-(S-glutathionyl)--methyldopamine; NADPH, reduced nicotinamide adenine dinucleotide phosphate; NO, nitric oxide; PGA, prostaglandin A; PGD, prostaglandin D; PGE, prostaglandin E; PGH, prostaglandin H.