Document Detail

Inhibitory effect of aluminium on calcium absorption in small intestine of rats with different thyroid hormone status.
MedLine Citation:
PMID:  19733399     Owner:  NLM     Status:  MEDLINE    
To analyse the influence of thyroid status on the effect of aluminium (Al) upon intestinal calcium (Ca) absorption, adult male Wistar rats with experimentally altered thyroid hormones circulating levels, were orally treated (o.g.) with 0 (control), or 50 mg elemental Al (as chloride)/kg body weight (b.w.) per day, for a 14 d period. Hyper- and hypo-thyroid conditions were respectively achieved by means of administration of either sodium levothyroxine (50 microg/kg b.w. per day, o.g.) or methimazole, a thyroxine synthesis inhibitor (1mg/kg b.w. per day, o.g.). In duodenum-jejunum segments, in vitro mucosa-to-serosa (45)Ca flux (JCa(ms)) and kinetics of (45)Ca uptake in isolated enterocytes, were determined. In serum, concentrations of thyroxine (T4) and triiodothyronine (T3) were measured by chemiluminescent enzyme immunoassay. Unlike non-Al-treated rats, JCa(ms) of Al-exposed rats decreased as serum levels of T4 and T3 increased, showing a significant inverse correlation in both cases (T4: r(2)=0.414, P=0.024; T3: r(2)=0.443, P=0.018). Enterocytes isolated from rats treated with Al plus thyroxine showed a reduction of both maximum Ca uptake (4.86+/-0.44 vs. 6.85+/-1.04 nmol Ca/mg protein, P<0.05) and K(m) (0.84+/-0.18 vs. 1.05+/-0.36 mM, P<0.05) when compared to control. The observed variability in the Al effect on Ca transport with thyroid status of rats could be reflecting a negative interaction of Al with thyroid hormone action mechanisms on intestinal Ca absorption, which would take place mainly at Ca entry into enterocyte from lumen.
Daniel Orihuela
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-08-14
Journal Detail:
Title:  Journal of inorganic biochemistry     Volume:  103     ISSN:  1873-3344     ISO Abbreviation:  J. Inorg. Biochem.     Publication Date:  2009 Nov 
Date Detail:
Created Date:  2009-10-26     Completed Date:  2010-02-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7905788     Medline TA:  J Inorg Biochem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1542-7     Citation Subset:  IM    
Laboratorio de Investigaciones Fisiol?gicas Experimentales, Facultad de Bioqu?mica y Ciencias Biol?gicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
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MeSH Terms
Aluminum / pharmacology*
Calcium / antagonists & inhibitors*,  metabolism
Enterocytes / drug effects*,  metabolism
Intestine, Small / drug effects*,  metabolism
Rats, Wistar
Thyroid Gland / drug effects,  metabolism*
Thyroxine / administration & dosage,  metabolism*
Triiodothyronine / administration & dosage,  metabolism*
Reg. No./Substance:
6893-02-3/Triiodothyronine; 7429-90-5/Aluminum; 7440-70-2/Calcium; 7488-70-2/Thyroxine

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

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