The formation of 4-hydroxy-2-nonenal (HNE) conjugates with glutathione (GSH) by Michael addition and subsequent cleavage to yield the related mercapturic acid (MA) conjugates are a major detoxication process. To characterize the metabolic pathways involved in the formation of urinary HNE-MA conjugates in the rat, the metabolism of HNE-thioethers (HNE- GSH, HNE-MA, and HNE-Cys) by rat liver and kidney cytosolic fractions was investigated. ...