English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/24037
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:


Regulation of iodothyronine deiodinase activity as studied in thyroidectomized rats infused with thyroxine or triiodothyronine

AuthorsEscobar-Morreale, Héctor F.; Obregón, María Jesús; Hernández, Arturo; Escobar del Rey, Francisco; Morreale de Escobar, Gabriella
Issue DateJun-1997
PublisherEndocrine Society
CitationEndocrinology 138(6): 2559-2568 (1997)
AbstractTo provide new insights into the in vivo regulation of iodothyronine deiodinases in the different tissues of the rat, we have evaluated the effects on these enzymatic activities of T4 or T3 infusions into thyroidectomized rats. Thyroidectomized rats were infused with placebo, T4, or T3. Placebo-infused intact rats served as euthyroid controls. Plasma and samples of cerebral cortex, brown adipose tissue, pituitary, liver, and lung were obtained after 12-13 days of infusion. Plasma TSH, plasma and tissue T4 and T3, and iodothyronine deiodinase activities were determined. Type II 5'-deiodinase (DII) was increased in cortex, brown adipose tissue, and pituitary from animals infused with placebo. DII activity returned to normal only with T4 infusion, remaining elevated in the animals infused with T3 alone despite normal tissue T3 concentrations. Cortex type III 5-deiodinase was only increased when hyperthyroidism was induced by infusion of T3. Liver type I 5'-deiodinase (DI) paralleled the changes in plasma and tissue T3 regardless of whether T4 or T3 was infused. On the contrary, the increase in lung DI, proportional to the increases in plasma and tissue T3, was higher when T4 was infused. As a rule, the tissues with DII presented a tighter homeostasis in their T3 concentrations than the tissues with DI. In conclusion, the regulation of iodothyronine deiodinases depends on the hormone infused into the thyroidectomized animals and on the tissue in which the deiodinase is studied, demonstrating the existence of tissue-specific regulation of its thyroid hormone concentrations.
Description10 pages, 7 figures, 2 tables.-- Presented in part at the 76th Annual Meeting of The Endocrine Society, Anaheim, CA, June 1994, and the 22nd Annual Meeting of the European Thyroid Association, Vienna, Austria, September 1994.
Publisher version (URL)http://dx.doi.org/10.1210/en.138.6.2559
Appears in Collections:(IIBM) Artículos
Files in This Item:
File Description SizeFormat 
Regulation of iodothyronine.pdf544,92 kBAdobe PDFThumbnail
Show full item record
Review this work

Related articles:

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.