Document Detail

High affinity of triiodothyronine (T3) for nonphenolic ring deiodinase and high affinity of tetraiodothyroacetic acid (TETRAC) for phenolic ring deiodinase in cultured monkey hepatocarcinoma cells and in rat liver homogenates.
MedLine Citation:
PMID:  6809451     Owner:  NLM     Status:  MEDLINE    
The metabolism of 3, 5-[3'-125I]triiodothyronin (T3) and 3-[3', 5'-125I]triiodothyronine (rT3) was studied in cultured monkey hepatocarcinoma cells (NCLP-6E), and the deiodinations of these iodothyronines were also investigated in cultured cell homogenates and in rat liver homogenates. The metabolites were analyzed by ion exchange column chromatography. For nonphenolic ring deiodination of 3, 5-[3'-125I]triiodothyronine, the order of the inhibitory effect of excess unlabeled iodothyronine or its analog was as follows: 3,3',5-triiodothyroinine greater than triiodothyroacetic acid greater than tetraiodothyroacetic acid greater than thyroxine. This order did not differ between in the intact cells (NCLP-6E) and their homogenates. The order of effectiveness of the excess unlabeled compounds on phenolic ring deiodination of 3-[3', 5'-125I]triiodothyronine in the intact cells was as follows: tetraiodothyroacetic acid greater than triiodothyroacetic acid, 3, 3', 5-triiodothyronine greater than thyroxine. This order was the same among monkey hepatocarcinoma cell homogenates, rat hepatoma cell homogenates and rat liver homogenates, and triiodothyroacetic acid was obviously more effective than 3, 3', 5-triiodothyronine. It was concluded that 3, 3', 5-triiodothyronine had the highest affinity for nonphenolic ring deiodinase among iodothyronines and their analogs used in the present study and that tetraiodothyroacetic acid and the highest affinity for phenolic ring deiodinase. It seems, therefore, that the metabolites derived from the thyroid hormones might contribute to deiodinations which involve activation and inactivation of the hormones.
K Sorimachi; Y Yasumura
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Endocrinologia japonica     Volume:  28     ISSN:  0013-7219     ISO Abbreviation:  Endocrinol. Jpn.     Publication Date:  1981 Dec 
Date Detail:
Created Date:  1982-10-12     Completed Date:  1982-10-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376546     Medline TA:  Endocrinol Jpn     Country:  JAPAN    
Other Details:
Languages:  eng     Pagination:  775-83     Citation Subset:  IM    
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MeSH Terms
Cell Line
Chromatography, Ion Exchange
Iodide Peroxidase / metabolism*
Liver / enzymology*
Liver Neoplasms / enzymology*
Peroxidases / metabolism*
Thyroxine / analogs & derivatives*,  metabolism
Triiodothyronine / analogs & derivatives,  metabolism*
Triiodothyronine, Reverse / metabolism
Reg. No./Substance:
51-24-1/3,3',5-triiodothyroacetic acid; 5817-39-0/Triiodothyronine, Reverse; 67-30-1/tetraiodothyroacetic acid; 6893-02-3/Triiodothyronine; 7488-70-2/Thyroxine; EC 1.11.1.-/Peroxidases; EC Peroxidase

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