| Literature DB >> 14757317 |
Matti Viluksela1, Atso Raasmaja, Margitta Lebofsky, Bernhard U Stahl, Karl K Rozman.
Abstract
Thyroid hormones play a complex role in the toxicity of polychlorinated dibenzo-p-dioxins and furans and related compounds. We investigated the toxicological significance of 5'-deiodinases I and II (5'-DI and 5'-DII) in the altered thyroid hormone status of TCDD-treated rats. Time courses and dose responses were determined for serum thyroxine (T4) and triiodothyronine (T3) levels, for 5'-DI activity in thyroid gland, liver and kidney, and for 5'-DII activity in brown adipose tissue (BAT). TCDD-treatment resulted in prompt and dose-dependent decrease in circulating T4 followed by a decrease in liver 5'-DI activity 1-2 days later and an apparent increase in BAT 5'-DII activity. Changes in liver 5'-DI and BAT 5'-DII activity were secondary to decreased T4 levels. Thyroid and kidney 5'-DI activities as well as circulating T3 levels were not affected. The results suggest that altered 5'-DI or 5'-DII activities do not significantly influence the circulating levels of T4 or T3 in TCDD-treated rats.Entities:
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Year: 2004 PMID： 14757317 DOI： 10.1016/j.toxlet.2003.10.025
Source DB: PubMed Journal: Toxicol Lett ISSN： 0378-4274 Impact factor: 4.372