COMPARATIVE METABOLISM OF 1,2,4-TRICHLOROBENZENE IN THE RAT AND RHESUS MONKEY

1,2,4.Trlchloro[’4Cjbenzene (TCB) was administered po (10 mg/kg) and iv (10 mg/kg) to rats and rhesus monkeys. Urine was collected at 24 hr and the major urinary metabolites were quantified and identified. By 24 hr, the monkey had excreted 22 % of the iv dose and roughly 40 % of the p0 dose in the urine. Less than 1 % of the radioactivity was found in the monkey’s feces. An isomeric pair of 3,4,6-trlchloro-3,5-cyclohexadlene-1,2-diol glucuronides accounted for between 48 and 61 % of the urinary metabolites. Glucuronides of 2,4,5- and 2,3,5-trichlorophenol (TCP) accounted for 14 to 37%, and unconjugated TCP’s accounted for 1-37 % of the monkey’s urinary metabolites. For the rat, 84 % of the po dose and 78 % of the iv dose were collected in the urine by 24 hr; 1 1 % and 7%, respec-tively, were the amounts collected in the feces. Two isomers, 2,4,5-and 2,3,5-, of acetyl-S-(trlchlorophenyl)-L-cysteine accounted for 60-62 % of the rat’s urinary metabolites. Free 2,4,5- and 2,3,5