Repeated dose toxicity and relative potency of 1,2,3,4,6,7-hexachloronaphthalene (PCN 66) 1,2,3,5,6,7-hexachloronaphthalene (PCN 67) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for induction of CYP1A1, CYP1A2 and thymic atrophy in female Harlan Sprague–Dawley rats
| Autor: | Nigel J. Walker, Daphne Vasconcelos, Molly Vallant, Abraham Nyska, Laurene M. Fomby, Michelle J. Hooth, Michael J. DeVito |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
medicine.medical_specialty
Polychlorinated Dibenzodioxins Dose Thymus Gland Naphthalenes Toxicology Article Rats Sprague-Dawley Atrophy Cytochrome P-450 CYP1A2 Internal medicine Cytochrome P-450 CYP1A1 Hydrocarbons Chlorinated medicine Animals Potency heterocyclic compounds Enzyme inducer Toxic equivalency factor Dose-Response Relationship Drug biology Chemistry CYP1A2 medicine.disease Rats Endocrinology Enzyme Induction Toxicity biology.protein Female Corn oil |
| Zdroj: | Toxicology. 301:85-93 |
| ISSN: | 0300-483X |
| DOI: | 10.1016/j.tox.2012.07.005 |
| Popis: | In this study we assessed the relative toxicity and potency of the chlorinated naphthalenes 1,2,3,4,6,7-hexachloronaphthalene (PCN 66) and 1,2,3,5,6,7-hexachloronaphthalene (PCN 67) relative to that of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Chemicals were administered in corn oil:acetone (99:1) by gavage to female Harlan Sprague–Dawley rats at dosages of 0 (vehicle), 500, 1500, 5000, 50,000 and 500,000 ng/kg (PCN 66 and PCN 67) and 1, 3, 10, 100, and 300 ng/kg (TCDD) for 2 weeks. Histopathologic changes were observed in the thymus, liver and lung of TCDD treated animals and in the liver and thymus of PCN treated animals. Significant increases in CYP1A1 and CYP1A2 associated enzyme activity were observed in all animals exposed to TCDD, PCN 66 and PCN 67. Dose response modeling of CYP1A1, CYP1A2 and thymic atrophy gave ranges of estimated relative potencies, as compared to TCDD, of 0.0015–0.0072, for PCN 66 and 0.00029–0.00067 for PCN 67. Given that PCN 66 and PCN 67 exposure resulted in biochemical and histopathologic changes similar to that seen with TCDD, this suggests that they should be included in the WHO toxic equivalency factor (TEF) scheme, although the estimated relative potencies indicate that these hexachlorinated naphthalenes should not contribute greatly to the overall human body burden of dioxin-like activity. |
| Databáze: | OpenAIRE |
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