Dietary exposure to 2,2´,4,4´-Tetrabromodiphenyl Ether (PBDE-47) alters thyroid status and thyroid hormone–regulated gene transcription in the pituitary and brain
- UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
- Sean C. Lema, Assistant Professor (Creator)
- Institution
- The University of North Carolina Wilmington (UNCW )
- Web Site: http://library.uncw.edu/
Abstract: BACKGROUND: Polybrominated diphenyl ether (PBDE) flame retardants have been implicated as
disruptors of the hypothalamic-pituitary-thyroid axis. Animals exposed to PBDEs may show
reduced plasma thyroid hormone (TH), but it is not known whether PBDEs impact TH-regulated
pathways in target tissues.
OBJECTIVE: We examined the effects of dietary exposure to 2,2´,4,4´-tetrabromodiphenyl ether
(PBDE-47)—commonly the highest concentrated PBDE in human tissues—on plasma TH levels
and on gene transcripts for glycoprotein hormone a-subunit (GPHa) and thyrotropin ß-subunit
(TSHß) in the pituitary gland, the autoinduced TH receptors a and ß in the brain and liver, and
the TH-responsive transcription factor basic transcription element-binding protein (BTEB) in
the brain.
METHODS: Breeding pairs of adult fathead minnows (Pimephales promelas) were given dietary
PBDE-47 at two doses (2.4 µg/pair/day or 12.3 µg/pair/day) for 21 days.
RESULTS: Minnows exposed to PBDE-47 had depressed plasma thyroxine (T4), but not
3,5,3´-triiodothyronine (T3). This decline in T4 was accompanied by elevated mRNA levels for TSHß
(low dose only) in the pituitary. PBDE-47 intake elevated transcript for TH receptor a in the brain of
females and decreased mRNA for TH receptor ß in the brain of both sexes, without altering these
transcripts in the liver. In males, PBDE-47 exposure also reduced brain transcripts for BTEB.
CONCLUSIONS: Our results indicate that dietary exposure to PBDE-47 alters TH signaling at multiple
levels of the hypothalamic-pituitary-thyroid axis and provide evidence that TH-responsive pathways
in the brain may be particularly sensitive to disruption by PBDE flame retardants.
KEY WORDS: basic transcription element-binding protein, brain, endocrine disruption, PBDE-47,
polybrominated diphenyl ethers, thyroid hormone, thyroid hormone receptor, thyroid-stimulating
hormone, thyrotropin. Environ Health Perspect 116:1694–1699 (2008). doi:10.1289/ehp.11570
available via http://dx.doi.org/ [Online 1 August 2008]
Dietary exposure to 2,2´,4,4´-Tetrabromodiphenyl Ether (PBDE-47) alters thyroid status and thyroid hormone–regulated gene transcription in the pituitary and brain
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Additional Information
- Publication
- Lema, S. C., Dickey, J. T., Schultz, I. R., & Swanson, P. (2008). Dietary exposure to 2,2´,4,4´-Tetrabromodiphenyl Ether (PBDE-47) alters thyroid status and thyroid hormone–regulated gene transcription in the pituitary and brain. Environmental Health Perspectives, 116, 1694–1699. doi:10.1289/ehp.11570. Reproduced with permission from Environmental Health Perspectives.
- Language: English
- Date: 2009
- Keywords
- Endocrine disrupting chemicals, Polybrominated diphenyl ethers, Thyroid hormones, Thyrotropin
- Subjects
- Polybrominated diphenyl ethers
- Thyroid hormones
- Thyrotropin
- Endocrine disrupting chemicals