Benzo(a)pyrene toxicokinetics in the cricket following injection into the haemolymph.

ABSTRACT

The metabolic disposition of (14)C-labelled benzo(a)pyrene (BP) in the cricket (Acheta domesticus) was investigated after injection into the haemolymph. (14)C-BP was taken up rapidly by the nerve cord, malpighian tubules, reproductive organs, gut, and musclecuticle of the cricket. The elimination half-lives of (14)C-BP in these tissues ranged from 8.9 to 17.8 h. The haemolymph (14)C-BP concentration-time curve could be described by a one-compartment open pharmacokinetic model. (14)C-BP was metabolized by the cricket mainly to unconjugated and conjugated BP metabolites since very little unchanged (14)C-BP was found in the excreta at 48 h post-dosing. GLPC-MSD and HPLC/ES-MS analyses showed the presence of at least two BP metabolites in the excreta. The BP metabolites were identified tenatively as the diol derivatives of benzo(a)pyrene and benzo(a)pyrene quinone.