Metabolism of 1,2-dichloroethane- 14 C in the mouse.

Abstract

Labelled 1,2‐dichloroethane (3.6 μci/mg), prepared by chlorination of ethylene‐14C, was injected intraperitoneally (0.05–0.17 g/kg) and the elimination of radioactivity was followed for 3 days. Depending on the dose 10–42% was expired unchanged and 12–15% as carbon dioxide. 51–73% of the dose was found in the urine, 0–0.6% in the faeces (contaminated with urine), and 0.6–1.3% remained in the animal. Examination of the urine by paper chromatography showed 3 major metabolites, chloroacetic acid, S‐carboxymethylcysteine, and thiodiacetic acid. The following amounts (% of urinary activity) were estimated by isotope dilution analysis: chloroacetic acid 6–23, S‐carboxymethylcysteine 44–46 (free) and 0.5–5 (conjugated), and thiodiacetic acid 33–34. These results are in good agreement with those previously obtained by the administration of chloroacetic‐1‐14C acid. It may therefore be suggested that the metabolism of 1,2‐dichloroethane proceeds mainly via chloroacetic acid. Isotope dilution analysis also revealed small amounts of 2‐chloroethanol and S,S'‐ethylene‐bis‐cysteine but no oxalic acid. Only a minor part of the activity might be due to S‐(β‐hydroxyethyl)‐cysteine and its mercapturic acid.