PUBLICATION
Modulation of steroidogenesis and xenobiotic biotransformation responses in zebrafish (Danio rerio) exposed to water-soluble fraction of crude oil
- Authors
- Arukwe, A., Nordtug, T., Kortner, T.M., Mortensen, A.S., and Brakstad, O.G.
- ID
- ZDB-PUB-080415-1
- Date
- 2008
- Source
- Environmental research 107(3): 362-370 (Journal)
- Registered Authors
- Keywords
- Steroidogenesis, Biotransformation system, Gene expression, Water-soluble fraction, Crude oil, Zebrafish
- MeSH Terms
-
- Animals
- Biotransformation
- Brain/drug effects
- Brain/enzymology
- Brain/metabolism
- Environmental Monitoring/methods*
- Gonadal Steroid Hormones/biosynthesis*
- Microsomes/drug effects
- Microsomes/enzymology
- Microsomes/metabolism
- Norway
- Petroleum/analysis*
- Solubility
- Water Pollutants, Chemical*/analysis
- Water Pollutants, Chemical*/pharmacokinetics
- Xenobiotics*/analysis
- Xenobiotics*/pharmacokinetics
- Zebrafish/metabolism*
- PubMed
- 18396270 Full text @ Environ. Res.
Citation
Arukwe, A., Nordtug, T., Kortner, T.M., Mortensen, A.S., and Brakstad, O.G. (2008) Modulation of steroidogenesis and xenobiotic biotransformation responses in zebrafish (Danio rerio) exposed to water-soluble fraction of crude oil. Environmental research. 107(3):362-370.
Abstract
The induction of CYP enzyme activities, particularly CYP1A1, through the aryl hydrocarbon receptor (AhR) in most vertebrate species is among the most studied biochemical response to planar and aromatic organic contaminant exposure. Since P450 families play central roles in the oxidative metabolism of a wide range of exogenous and endogenous compounds, interactions between the biotransformation processes and reproductive physiological responses are inevitable. Steroidogenesis is the process by which specialized cells in specific tissues, such as the gonad, brain (neurosteroids) and kidney, synthesize steroid hormones. In the present study, we evaluated the effects of water-soluble fraction (WSF) of crude oil on the xenobiotic by which specialized cells in specific tissues, such as the gonad, brain (neurosteroids) and kidney, synthesize steroid hormones. In the prbiotransformation and steroidogenic processes in the head (brain) and whole-body tissue of a model species by transcript analysis using quantitative (real-time) polymerase chain reaction (qPCR), enzyme activities and steroid hormone (testosterone: T and 17beta-estradiol: E2) levels using enzyme immune assay (EIA). Our data showed that exposure of fish to WSF produced an apparent concentration-specific increase of AhR1, CYP1A1 and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) mRNA levels, and decrease of AhR2. On the activity level, WSF produced concentration-specific increase of ethoxyresorufin O-deethylase (EROD), benzyloxyresorufin (BROD) methoxyresorufin (MROD) and pentoxyresorufin (PROD) activities in whole-body tissue. In the steroidogenic pathway, WSF exposure produced apparent concentration-specific decrease of ERalpha and ERbeta, steroidogenic acute regulatory (StAR) protein, cytochrome P450 side-chain cleavage (P450scc), P450aromA and P450aromB mRNA expression. For steroid hormones, while T levels decreased, E2 levels increased in an apparent WSF concentration-specific manner. In general, the xenobiotic biotransformation and estrogenic responses showed negative relationship after exposure of zebrafish to WSF, suggesting an interaction between these physiological pathways. The relationship between WSF mediated changes in brain StAR, P450scc, 3beta-HSD, ERalpha, ERbeta, P450aromA, P450aromB and whole-body steroid hormone levels suggests that the experimental animals might be experiencing altered neurosteroidogenesis probably through increased activity level of the biotransformation system. Thus, these responses might represent sensitive diagnostic tools for short-term and acute exposure of fish or other aquatic organisms to WSF.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping