Abstract

4,4'-Methylenebis(2-chloroaniline) (MBOCA) metabolism in canine liver and kidney slices was investigated using HPLC to separate the metabolites. Liver slices metabolized 5-10% of the 14C-MBOCA in 60 min and produced seven metabolites resolved by HPLC. The major metabolite, representing approximately 80% of the metabolism, was 2-amino-5-[(4-amino-3-chlorophenyl)methyl]-3-chlorophenyl hydrogen sulfate, previously identified as the major urinary metabolite in dogs. An MBOCA-glucoside was identified by mild acid hydrolysis, which released MBOCA and glucose. An O-glucuronide was characterized as labile to beta-glucuronidase, stabile to arylsulfatase, and mild acid. It was formed in increased amounts when 2,6-dichloro-4-nitrophenol (DCNP) was added to the incubation. Two other glucuronide metabolites were labile to mild acid and beta-glucuronidase, stabile to arylsulfatase, and were formed in decreased amounts in the presence of D-(+)-galactosamine (D-gal) and p-nitrophenyl sulfate (PNPS). Renal cortical slices metabolized 3-5% of the 14C-MBOCA in 90 min, producing six metabolites. Based on retention time and lability to hydrolysis, three of these, the MBOCA-glucoside, a glucuronide, and 2-amino-5-[(4-amino-3-chlorophenyl)methyl]-3-chlorophenyl hydrogen sulfate were also found as kidney metabolites. One additional sulfur-containing metabolite was labile to mild acid and arylsulfatase. The major kidney metabolite represented 25-40% of the metabolism and was unaffected by mild acid, beta-glucuronidase, arylsulfatase, DCNP, and D-gal. Covalent binding in liver slices was 20-27 pmol/mg of wet weight/60 min and in kidney was 9-13 pmol/mg of wet weight/90 min.(ABSTRACT TRUNCATED AT 250 WORDS)