Perfluorooctane sulfonate (PFOS) is a perfluoroalkyl acid that has unique surfactant properties and is used widely in industrial and household products. Furthermore, PFOS is an environmentally persistent compound, and its presence has been detected in both humans and wildlife. The maternal and developmental toxicities of PFOS were evaluated in Sprague-Dawley rats given 1, 2, 3, 5, or 10 mg/kg PFOS daily from gestational day (GD) 2 to GD 20. Controls received 0.5% Tween 20 vehicle (1 ml/kg). Serum thyroxine (T4) and triiodothyronine (T3) in the PFOS-treated dams were significantly reduced as early as one week after chemical exposure, although no feedback response of thyroid stimulating hormone (TSH) was observed. The effects of sub-chronic exposure to PFOS (3 mg/kg/day for eight days) on thyroid hormone economy are further characterized in adult male rats, and the thyrotoxic effects of PFOS are compared to propylthiouracil (PTU), a classic goitrogen. This work substantiates the endocrine disrupting effects of PFOS, but fails to provide evidence for its physiological consequences in comparison to PTU based on two biomarkers of hypothyroidism: myocardial beta-adrenergic receptor density and hepatic malic enzyme activity. Furthermore, in vitro static incubation of the pituitary is used to investigate the observed lack of response of the hypothalamic-pituitary-thyroid axis. PFOS does not significantly alter thyrotropin releasing hormone (TRH) induced secretion of TSH from the pituitary. Therefore, it is not likely that PFOS-induced changes in circulating thyroid hormones are due to a disruption at the level of the pituitary.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-06242005-103138 |
| Date | 27 June 2005 |
| Creators | Thibodeaux, Julie Rene |
| Contributors | Jill Barnes, Christopher Lau, John M. Rogers |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-06242005-103138/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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