The toxicokinetics of (1R, cis)- and (1R, trans)- tetramethrin in the isolated perfused rat liver

1. The toxicokinetics of cis- and trans-tetramethrin isomers were investigated using the isolated perfused rat liver preparation. 2. The concentration of cis- and trans-tetramethrin decreased rapidly in the plasma perfusate and was initially replaced by N-(hydroxymethyl)3,4,5,6-tetrahydrophthalimide (MTI) and then by 3,4,5,6-tetrahydrophthalimide (TPI). Plasma perfusate concentrations of the intact cis-isomer were higher than those of the trans-isomer. Concentrations of MTI and TPI were higher in livers treated with the trans-isomer. 3. Tetramethrin and its metabolites were rapidly excreted in the bile. Bile from livers perfused with trans-isomer contained higher concentrations of parent isomer and metabolites MTI and TPI, than did bile from livers treated with the cis-isomer.