Abstract

The metabolic fate of U- 14C-2,3,5,6-tetrachloronitrobenzene (tecnazene) has been determined in the male and female rat following a single dose of 1 mg/kg and in surgically prepared, bile-duct-cannulated rats following a single oral dose of 135 mg/kg. Radioactivity in the female rat was excreted mainly in urine (82%). The male rat, however, excreted approximately equal amounts of radioactivity in urine and faeces (the latter via bile). The principal metabolic pathway was conjugation with glutathione (GSH) and concomitant nitro-displacement. The GSH-conjugate and related metabolites were excreted in the bile and ultimately in the urine as the mercapturic acid conjugate. The cysteine conjugate underwent β-lyase-mediated metabolism to yield a thiol that underwent subsequent methylation to the thioanisole followed by S-oxidation. A novel tetrachloromethyldisulphide metabolite was also formed.