RP10 Aquatic Ecotoxicology
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(TUR-1117-827583-1) Identification of metabolites from alkyl-anthracene compounds in rainbow trout (Oncorhynchus mykiss).

Turcotte, D¹, Abudulai, N¹, Witherly, K, Hodson, P¹, Brown, R¹, ¹ School of Environmental Studies, Queen's University, Kingston, Ontario, Canada

ABSTRACT- Fish are often exposed to polycyclic aromatic hydrocarbons and the toxicity and metabolism of those toxicants is still not completely understood. The excretion mechanism of xenobiotics is composed of a two-step metabolic process. The first step (phase I), which renders compounds more polar, involves cytochrome P450 (CYP) enzymes. The second step (phase II) involves the conjugation of phase I intermediates with glucuronic acid, glutathione, sulfate or amino acid moieties. CYP enzymes, although part of a mechanism of detoxification, often enhance the general toxicity of anthracene (ANT) derivatives by forming reactive oxygen species. The purpose of this study was to investigate the metabolism of ANT and alkyl-ANTs by rainbow trout (Oncorhynchus mykiss). Phase I metabolites were investigated in vitro by incubating single ANT and alkyl-ANTs with postmitochondrial supernatant fraction (S9 fraction). Phase II metabolites were investigated in vivo by exposing rainbow trout to the same compounds through intraperitoneal injection for a period of 24 hours, after which the gall bladder was sampled. Phase I and biliary phase II metabolites were identified using HPLC coupled with a UV-diode array absorbance detector. Alkyl-chain and ring hydroxylated compounds were found as phase I intermediates. Alkyl-chain and ring glucuronide conjugates were also found for all alkyl-ANTs investigated. Ring conjugates only were found for ANT, as expected. Further metabolized glucuronide conjugates were also detected which are suspected to be diglucuronide conjugates.

Key words: anthracene, metabolism, fish, pah