| Activities of UDP-glucuronyltransferase, beta-glucuronidase and deiodinase types I and II in hyper- and hypothyroid rats. | |
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MedLine Citation:
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PMID: 15171687 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We have investigated the hypothesis that uridine 5'-diphosphate (UDP)-glucuronyltransferases (UGTs) and beta-glucuronidase are jointly involved in a mechanism for the storage and mobilization of iodothyronine metabolites in liver, kidney, heart and brain. Specifically, we predicted UGT activities to decrease and increase respectively, and beta-glucuronidase activity to increase and decrease respectively in hypo- and hyperthyroidism. To this end we have studied the effects of thyroid status on the activities of different enzymes involved in thyroid hormone metabolism in liver, kidney, heart and brain from adult rats with experimentally induced hypo- and hyperthyroidism. We used whole organ homogenates to determine the specific enzyme activities of phenol- and androsteron-UGT, beta-glucuronidase, as well as iodothyronine deiodinase types I and II. Deiodinase type I activities in liver and kidney were decreased in hypothyroid animals and, in liver only, increased in hyperthyroidism. Deiodinase type II activity was increased in hyperthyroid rat kidney only. Interestingly, in the heart, deiodinase type I-specific activity was increased fourfold, although the increase was not statistically significant. Cardiac deiodinase type I activity was detectable but not sensitive to thyroid status. Hepatic phenol-UGT as well as androsteron-UGT activities were decreased in hypothyroid rats, with specific androsteron-UGT activities two to three orders of magnitude lower than phenol-UGT activities. Both UGT isozymes were well above detection limits in heart, but appeared to be insensitive to thyroid status. In contrast, cardiac beta-glucuronidase activity decreased in hypothyroid tissue, whereas the activity of this enzyme in the other organs investigated did not change significantly. In summary, cardiac beta-glucuronidase, albeit in low levels, and hepatic phenol-UGT activities were responsive only to experimental hypothyroidism. Although a high basal activity of the pleiotropic beta-glucuronidase masking subtle activity changes in response to thyroid status cannot be ruled out, we conclude that hepatic, renal and cardiac UGT and beta-glucuronidase activities are not regulated reciprocally with thyroid status. |
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Authors:
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S M van der Heide; B J L J Joosten; M E Everts; P H M Klaren |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The Journal of endocrinology Volume: 181 ISSN: 0022-0795 ISO Abbreviation: J. Endocrinol. Publication Date: 2004 Jun |
Date Detail:
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Created Date: 2004-06-02 Completed Date: 2004-07-15 Revised Date: 2009-11-03 |
Medline Journal Info:
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Nlm Unique ID: 0375363 Medline TA: J Endocrinol Country: England |
Other Details:
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Languages: eng Pagination: 393-400 Citation Subset: IM |
Affiliation:
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Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, PO Box 80158, 3508 TD Utrecht, The Netherlands. s.vanderheide@vet.uu.nl |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Brain / enzymology Glucuronidase / metabolism* Glucuronosyltransferase / antagonists & inhibitors, metabolism* Hyperthyroidism / enzymology Hypothyroidism / enzymology Iodide Peroxidase / metabolism* Isoenzymes / metabolism* Kidney / enzymology Liver / enzymology Models, Animal Myocardium / enzymology* Ouabain / metabolism Pentachlorophenol / pharmacology Rats Rats, Wistar Thyroid Diseases / enzymology* |
| Chemical | |
Reg. No./Substance:
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0/Isoenzymes; 630-60-4/Ouabain; 87-86-5/Pentachlorophenol; EC 1.11.1.8/Iodide Peroxidase; EC 2.4.1.17/Glucuronosyltransferase; EC 3.2.1.31/Glucuronidase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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