title: Benzo[a]pyrene toxicokinetics in rainbow trout (Oncorhynchus mykiss) acclimated to different salinities.
abstract: The effects of environmental salinity on the distribution, metabolism, and elimination of benzo[a]pyrene (B[a]P) were examined in mature rainbow trout. Trout acclimated to either fresh water (0 ppt, FW) or sea water (20 ppt, SW) for 3 weeks received a single 10 mg/kg intra-arterial injection of [(3)H]-benzo[a]pyrene (B[a]P) at their acclimation salinity or when subjected to an acute salinity change. Statistically significant differences in the percent body burden of B[a]P-derived radioactivity in various tissues were seen between fish in FW versus SW. Significant differences in the distribution of B[a]P and its metabolites were also noted when fish were subjected to an acute salinity change after chemical injection. Modulation of B[a]P metabolism by environmental salinity included: (1) significant differences in the proportions of Phase I metabolites in the bile of FW- (2.3%) versus SW-acclimated (14.1%) fish, and (2) alterations in the accumulations of specific metabolites (predominantly t-9, 10-dihydrodiol-B[a]P in FW fish, and 3-hydroxy-B[a]P in SW fish). The percentages of the [(3)H]-B[a]P dose eliminated by 48 h was similar in FW and SW fish, but decreased in fish subjected to an acute salinity change (FW 98.8% eliminated, FW:SW 90.4%, SW 98.1%, and SW:FW 93.1%). Pharmacokinetic modeling confirmed that acute salinity changes can result in longer terminal half-lives and slower total body clearances of B[a]P.
authors.affiliation: Department of Pharmacology and Toxicology, University of Western Ontario, London, Ontario, Canada N6A 5C1.
authors.forename: J M
authors.initials: JM
authors.lastname: Seubert
authors.forename: C J
authors.initials: CJ
authors.lastname: Kennedy
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001564:Benzo(a)pyrene / Q000493:pharmacokinetics* / Q000633:toxicity; D002273:Carcinogens / Q000493:pharmacokinetics* / Q000633:toxicity; D006207:Half-Life; D017686:Oncorhynchus mykiss / Q000502:physiology*; D012965:Sodium Chloride; D014867:Water / Q000737:chemistry
chemical_list: D002273:Carcinogens; D014867:Water; D001564:Benzo(a)pyrene; D012965:Sodium Chloride