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Published on: August 8, 2020
Multiple molecular effect pathways of an environmental oestrogen in fish
Amy L Filby1, Karen L Thorpe, Charles R Tyler
1Environmental and Molecular Fish Biology Group, School of Biosciences, Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter, Devon EX4 4PS, UK. a.l.filby@exeter.ac.uk
Journal of Molecular Endocrinology
|August 12, 2006
Summary
Environmental estrogens like 17beta-oestradiol (E2) disrupt fish physiology beyond reproduction. Exposure impacts growth, thyroid, and interrenal functions, affecting multiple genes and tissues in fathead minnow (Pimephales promelas).
Area of Science:
- Endocrinology
- Environmental Toxicology
- Fish Biology
Background:
- Environmental estrogens pose complex risks to aquatic ecosystems.
- Existing research often underestimates the broad physiological impacts of estrogenic compounds on fish.
Purpose of the Study:
- To investigate the effects of 17beta-oestradiol (E2) on gene expression related to growth, development, thyroid, interrenal, and reproductive functions in fathead minnow (Pimephales promelas).
- To explore the complex interrelationships and pathways of environmental estrogen action in fish.
Main Methods:
- Adult fathead minnow were exposed to 35 ng E2/l for 14 days.
- Gene expression analysis was performed for growth hormone (GH), GH receptor (GHR), IGF-I, IGF-I receptor (IGF-1R), thyroid hormone receptors (THRA, THRB), glucocorticoid receptor (GR), sex-steroid receptors, and other reproductive genes.
- Responses were assessed across multiple tissues (pituitary, brain, liver, gonad, gill) and sexes.
Main Results:
- Exposure to E2 induced classic estrogenic biomarkers (vitellogenin) and impacted the reproductive axis, including feminization of steroidogenic enzyme expression and suppressed testis differentiation genes.
- E2 triggered significant changes in the expression of genes related to growth, thyroid, and interrenal functions across various tissues.
- Gene expression responses to E2 were tissue- and sex-specific, highlighting complex endocrine interactions (e.g., differential IGF-I regulation in brain vs. gill, and opposite responses in males vs. females).
Conclusions:
- Environmental estrogens exert wide-ranging physiological effects on fish, extending beyond reproductive disruption.
- Understanding complex endocrine interactions is crucial for predicting the health consequences of environmental estrogen exposure in aquatic organisms.
- The study underscores the need for a broader assessment of environmental estrogen impacts on fish physiology.
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