Document Detail

Effects of iodothyronines on the hepatic outer-ring deiodinating pathway in killifish.
MedLine Citation:
PMID:  14697306     Owner:  NLM     Status:  MEDLINE    
Substrate availability has been thought to be a major regulator of the outer-ring deiodinating pathway (ORD) in fish. However, current information strongly suggests that while fish iodothyronine deiodinase type 2 (D2) responds to iodothyronines in the same manner as its mammalian counterpart, fish deiodinase type 1 (D1) exhibits a distinct response. Furthermore, 3,5-T2, generally considered to be an inactive product of iodothyronine metabolism, has recently been described as bioactive, but its effects upon D1 and D2 are not yet known. We examined the effect that short-term immersion in T4, T3, and 3,5-T2 (0.1 microM; 12 or 24 h) exerts on both D1 and D2 activities and on the levels of expression of D1 and D2 mRNAs in killifish liver. In agreement with previous reports in teleosts, no iodothyronine exerted a significant effect on D1 enzymatic activity. However, all three iodothyronines significantly decreased D2 activity. Furthermore, at 24 h post-immersion T4, T3, and 3,5-T2 inhibited both D1 and D2 transcription. Together, the present results confirm the differential effect of iodothyronines upon the hepatic ORD pathway in fish and show that this effect can occur at a transcriptional level. Furthermore, we provide the first evidence that 3,5-T2 can affect both activity and transcription of hepatic deiodinases in teleosts.
Carlota García-G; Michael C Jeziorski; Carlos Valverde-R; Aurea Orozco
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  General and comparative endocrinology     Volume:  135     ISSN:  0016-6480     ISO Abbreviation:  Gen. Comp. Endocrinol.     Publication Date:  2004 Jan 
Date Detail:
Created Date:  2003-12-30     Completed Date:  2004-08-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370735     Medline TA:  Gen Comp Endocrinol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  201-9     Citation Subset:  IM    
Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus UNAM-UAQ-Juriquilla, Queretaro 76230, Qro, Mexico.
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MeSH Terms
Diiodothyronines / pharmacology*
Enzyme Activation / drug effects
Fundulidae / metabolism*
Gene Expression Regulation, Enzymologic / drug effects
Iodide Peroxidase / genetics,  metabolism*
Liver / enzymology*
Polymerase Chain Reaction / methods
RNA, Messenger / analysis
Thyroid Gland / metabolism*
Thyroxine / pharmacology
Triiodothyronine / pharmacology
Reg. No./Substance:
0/Diiodothyronines; 0/RNA, Messenger; 534-51-0/3,5-diiodothyronine; 6893-02-3/Triiodothyronine; 7488-70-2/Thyroxine; EC 1.11.1.-/iodothyronine deiodinase type I; EC 1.11.1.-/iodothyronine deiodinase type II; EC Peroxidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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