The metabolism of 1-bromopropane in the rat has been re-investigated. The previously known metabolites have been isolated and confirmed as the three mercapturic acids N-acetyl-S-propyl cysteine, N-acetyl-S-propyl cysteine-S-oxide and N-acetyl-S-(2-hydroxypropyl)cysteine. 2. Three further metabolites have been isolated from the urine of rats treated with 4-bromopropane. These have been identified as 3-bromopropionic acid and the mercapturic acids N-acetyl-S-(3-hydroxypropyl)cysteine and N-acetyl-S-(2-carboxyethyl)cysteine. 3. The metabolites of 3-bromopropanol and 3-chloropropanol in the rat have been shown to be the mercapturic acids N-acetyl-S-(3-hydroxypropyl)cysteine and N-acetyl-S-(2-carboxyethyl)cysteine and the corresponding 2-carboxyethyl halide. 4. Studies with 1-bromopropane and the 3-halopropanols in vitro indicate that oxidation of C3 and C2 of 1-bromopropane occurs before conjugation of the alkyl group with glutathione. The implications of these studies are discussed in relation to the mechanism of the biosynthesis of the S-(2-hydroxyalkyl)mercapturic acid metabolites derived from the alkyl halides.
