Activity of Phase I and Phase II enzymes of the benzo[a]pyrene transformation pathway in zebrafish (Danio rerio) following waterborne exposure to arsenite

E. David Thompson, Karen E. Burwinkel, Anil K. Chava, Emily G. Notch, Gregory D. Mayer

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

The environmental pollutants inorganic arsenic (iAs) and benzo[a]pyrene (B[a]P) are carcinogens often found together in groundwater. The hepatic metabolism of B[a]P is a multi-step process requiring several Phase I and Phase II enzymes, notably cytochrome p450 1A (CYP1A), epoxide hydrolase (EH), and glutathione S-transferase (GST). The purpose of this study was to examine the effect of arsenite (As(III)) on the activity of these enzymes in vivo utilizing adult zebrafish (Danio rerio). Zebrafish were exposed to either 0.4 μM B[a]P, 0.4 μM B[a]P. +. 0.4 μM As(III), 0.4 μM B[a]P. +. 8 μM As(III), 0.4 μM As(III), or 8 μM As(III) for 7. days. Co-exposures to As(III) and B[a]P led to significant decreases in CYP1A enzyme activity (approximately 3-fold) when compared to exposure to B[a]P alone. No similar effects occurred with EH or GST, although B[a]P exposure did significantly increase EH activity. Furthermore As(III) and B[a]P co-exposures significantly decreased CYP1A transcript levels (up to 35-fold) when compared to B[a]P. However, B[a]P-induced CYP1A protein levels remained elevated following co-exposures to As(III). This evidence suggests that As(III) has the potential to modify components of the B[a]P biotransformation pathway in vivo via a disruption of CYP1A activity by way of both pre- and post-translational mechanisms.

Original languageEnglish
Pages (from-to)371-378
Number of pages8
JournalComparative Biochemistry and Physiology - C Toxicology and Pharmacology
Volume152
Issue number3
DOIs
StatePublished - 2010

Keywords

  • Arsenic
  • Benzo[a]pyrene
  • Cytochrome p4501A
  • Enzyme activity
  • Epoxide hydrolase
  • Expression

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