QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Behne, D. Articles by Meinhold, H. Search for Related Content PubMed PubMed Citation Articles by Behne, D. Articles by Meinhold, H.

Type I Iodothyronine Deiodinase Activity after High Selenium Intake, and Relations between Selenium and Iodine Metabolism in Rats¹

Hahn-Meitner-Institut Berlin ^* Klinikum Steglitz, Freie Universität Berlin, D-1000 Berlin, Germany

Type I iodothyronine deiodinase (I-D), which catalyzes the production of the thyroid hormone 3,3',5-triiodothyronine from thyroxine, has recently been identified as a selenoenzyme. It is therefore of interest to investigate the relationships between selenium and iodine metabolism. In the livers of Se-deficient rats I-D activity was inhibited; the production of 3,3',5-triiodothyronine and 3,3'-diiodothyronine from added thyroxine was decreased by >95% relative to Se-adequate controls. The hepatic I-D activity was also reduced in rats fed a diet with a low iodine concentration. Unaltered glutathione peroxidase activities in liver and plasma of these rats suggest, however, that with normal Se intake this metabolic pathway of Se is not affected by iodine depletion. When rats were administered ⁷⁵Se-labeled selenium at levels equal to the amounts ingested from diets with Se concentrations of 0.3 or 2 mg Se/kg, greater Se concentrations were found in the thyroid and liver of the animals receiving the higher dosage. The thyroidal 3,3',5-triiodothyronine and thyroxine concentrations, however, were comparable in rats fed diets with 0.3 mg Se/kg diet as selenite and 2 mg Se/kg as selenite or L-selenomethionine. The measurement of the hepatic I-D and glutathione peroxidase activities in these animals showed that excessive Se supply does not elevate the activities of the two enzymes but might even have the opposite effect. At high Se intake tissue Se concentration cannot therefore be used as indicator of the selenoenzyme activities.

KEY WORDS: • type I iodothyronine deiodinase • glutathione peroxidase • selenite • selenomethionine • rats

¹ Partly supported by grants from the Deutsche Forschungsgemeinschaft.

Manuscript received 23 July 1991. Revision accepted 28 January 1992.

This article has been cited by other articles:

				M. A. Ward, T. L. Neville, J. J. Reed, J. B. Taylor, D. M. Hallford, S. A. Soto-Navarro, K. A. Vonnahme, D. A. Redmer, L. P. Reynolds, and J. S. Caton Effects of selenium supply and dietary restriction on maternal and fetal metabolic hormones in pregnant ewe lambs J Anim Sci, May 1, 2008; 86(5): 1254 - 1262. [Abstract] [Full Text] [PDF]

				R. Irons, B. A. Carlson, D. L. Hatfield, and C. D. Davis Both Selenoproteins and Low Molecular Weight Selenocompounds Reduce Colon Cancer Risk in Mice with Genetically Impaired Selenoprotein Expression J. Nutr., May 1, 2006; 136(5): 1311 - 1317. [Abstract] [Full Text] [PDF]

				J. Zhang, V. Svehlikova, Y. Bao, A.F. Howie, G. J. Beckett, and G. Williamson Synergy between sulforaphane and selenium in the induction of thioredoxin reductase 1 requires both transcriptional and translational modulation Carcinogenesis, March 1, 2003; 24(3): 497 - 503. [Abstract] [Full Text] [PDF]