PUBLICATION
Disruption of the hypothalamic-pituitary-thyroid axis in zebrafish embryo-larvae following waterborne exposure to BDE-47, TBBPA and BPA
- Authors
- Chan, W.K., and Chan, K.M.
- ID
- ZDB-PUB-111122-38
- Date
- 2012
- Source
- Aquatic toxicology (Amsterdam, Netherlands) 108: 109-111 (Journal)
- Registered Authors
- Chan, King-Ming
- Keywords
- brominated flame retardant, gene induction, hypothalamic-pituitary-thyroid axis, real-time polymerase chain reaction, zebrafish
- MeSH Terms
-
- Animals
- Benzhydryl Compounds
- Embryo, Nonmammalian/drug effects
- Flame Retardants/toxicity*
- Gene Expression Profiling
- Gene Expression Regulation, Developmental/drug effects
- Halogenated Diphenyl Ethers
- Hypothalamus/drug effects*
- Lethal Dose 50
- Phenols/toxicity
- Pituitary Gland/drug effects*
- Polybrominated Biphenyls/toxicity
- Thyroid Gland/drug effects*
- Thyroid Hormones/metabolism
- Toxicity Tests, Acute
- Water Pollutants, Chemical/toxicity*
- Zebrafish/embryology
- Zebrafish/physiology*
- PubMed
- 22100034 Full text @ Aquat. Toxicol.
- CTD
- 22100034
Citation
Chan, W.K., and Chan, K.M. (2012) Disruption of the hypothalamic-pituitary-thyroid axis in zebrafish embryo-larvae following waterborne exposure to BDE-47, TBBPA and BPA. Aquatic toxicology (Amsterdam, Netherlands). 108:109-111.
Abstract
We performed waterborne exposures of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), tetrabromobisphenol A (TBBPA) or bisphenol A (BPA) on zebrafish (Danio rerio) embryo-larvae and quantitatively measured the expression of genes belonging to the hypothalamic-pituitary-thyroid (HPT) axis to assess for adverse thyroid function. For analysis on the effects of BDE-47, TBBPA and BPA on the hypothalamic-pituitary-thyroid genes, zebrafish embryo-larvae were acutely exposed to lethal concentrations of the chemical agents in order to determine the 96h-LC50 (96h lethal median concentration) and 96h-EC50 (96h effective median concentration) values. Further exposures at sub-lethal concentrations were then carried out and total RNA samples were extracted to quantify the mRNA expression levels of the genes of interest. In larvae, BDE-47 was found to have significantly induced many genes of interest, namely thyroglobulin, thyroid peroxidase, thyroid receptors α and β, thyroid stimulating hormone, and transthyretin. TBBPA only significantly induced three genes of interest (thyroid receptor α, thyroid stimulating hormone, and transthyretin) while BPA only induced thyroid stimulating hormone. In embryos, BDE-47 significantly induced the sodium iodide symporter and thyroid stimulating hormone. TBBPA significantly induced thyroid receptor α and thyroid stimulating hormone, while BPA did not significantly induce any of the genes. Most genes were only induced at the 75% 96h-LC50 or 96h-EC50 value; however, thyroid peroxidase and thyroid stimulating hormone demonstrated upregulation in a level as little as the 10% 96h-LC50 value. The present study provides a new set of data on zebrafish mRNA induction of hypothalamic-pituitary-thyroid genes from exposure to BDE-47, TBBPA, or BPA. This information would serve useful for elucidating the toxicological mechanism of brominated flame retardants, assessing appropriate safety levels in the environment for these compounds, as well as serve as a reference for other man-made contaminants.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping