Oxidative metabolism activity in Hydra Attenuata exposed to carbamazepine

The cnidarian Hydra attenuata has become an increasingly popular bioindicator species owing to its sensitivity to various environmental contaminants. In this study, we examined the oxidative metabolism and biotransformation capacity of Hydra attenuata exposed to the drug carbamazepine (CBZ), commonly found in municipal wastewaters. The organisms were first exposed to increasing concentrations of CBZ for 48 h at 20^oC. They were then tested for heme oxidase (HO) and lipid peroxidation (LPO) in addition to phase I (ethoxy/ benzyloxyresorufin, dibenzyloxyfluorescein and 3-cyano-7-ethoxy-coumarin de-alkylase activities) and phase II (glutathione S-transferase and sulfotransferase activities) biotransformation reactions. Results showed that exposure to CBZ led to the induction of HO activity and LPO in Hydra. The activity of benzyloxyresorufin de-alkylase was induced by CBZ, while no significant change in 7-ethoxyresorufin O-deethylase activity took place. Glutathione Stransferase activity was also induced at low concentrations, but sulfotransferase activity was elevated only at the highest concentration tested. Hydra appears to possess both mixed function oxidase and conjugation capabilities that are inducible upon exposure to this xenobiotic. The estimated threshold effect concentration of CBZ on both oxidative and conjugative metabolisms in Hydra was found at environmentally relevant concentrations for this pharmaceutical.