The comparative metabolism of 2-bromoethanol and ethylene oxide in the rat.

1. The metabolism of 2-bromo[U-14C]ethanol an [U-14C]ethylene oxide has been studied in the rat. 2. As both compounds give rise to similar amounts of two urinary metabolites, identified as S-(2-hydroxyethyl)cysteine and N-acetyl-S-(2-hydroxyethyl)cysteine, it is proposed that 2-bromoethanol is converted into ethylene oxide in vivo. 3. A minor metabolite of 2-bromoethanol has been identified as N-acetyl-S-(carboxymethyl)cysteine. 4. The metabolism of bromoacetaldehyde and bromoacetic acid has been investigated; N-acetyl-S-(carboxymethyl)cysteine had been shown to be a common urinary metabolite. 5. An oxidative metabolic pathway is proposed for 2-bromoethanol, via bromoacetaldehyde and bromoacetic acid, to N-acetyl-S-(carboxymethyl)cysteine.