2,2',4,5,5'-Pentachlorobiphenyl: comparative metabolism in mink (Mustela vison) and mouse

The metabolism of 14C-labeled 2,2',4,5,5'-pentachlorobiphenyl was studied in mink (Mustela vison) and, for comparison in the mouse (C57Bl). Both species were dosed orally and kept in metabolism cages for 5 days. Distribution in tissues and excretion rate were determined radiometrically, and metabolites were analyzed by GC/MS. Within 5 days, the mink excreted 17% of the dose, and the mouse excreted 74%, mainly via the feces. For both species, the excreted radioactivity consisted primarily of metabolites, a large proportion of which were covalently bound to macromolecules and to lipids. A smaller proportion consisted of water-soluble metabolites. Phenolic and, in trace amounts, methylsulfonyl metabolites were also excreted. In the mink, a salivary gland in the neck region demonstrated the highest concentration of radiolabeled material of all tissues examined (3 times higher than in adipose tissue and liver on a lipid weight basis). The radioactive material in the salivary gland consisted of the parent compound and phenolic and methylsulfonyl metabolites. In the mouse, the highest concentration of 14C was found in the lund and consisted of 4-methylsulfonyl-2,2',4',5,5'-pentachlorobiphenyl. Hydroxylated and methylsulfonyl metabolites were retained to various degrees in tissues of both species. The mink, but not the mouse, also formed metabolites that were hydroxylated in the trichlorinated phenyl ring.