Effect of iodine deficiency and cold exposure on thyroxine 5'-deiodinase activity in various rat tissues

Pazos‐Moura, Carmen C.; Moura, Egberto Gaspar de; Dorris, Martha L.; Rehnmark, Stefan; Meléndez, Loyda M.; Silva, J. E.; Taurog, Alvin

doi:10.1152/ajpendo.1991.260.2.e175

Cited by 44 publications

(40 citation statements)

References 24 publications

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“…The main consequences of iodine deficiency are goiter, hypothyroxinemia (242), increased NIS expression (331), increased monoiodotyrosine (MIT)/diiodotyrosine (DIT) and T 3 /T 4 ratios within the thyroglobulin (332,333), preferential T 3 synthesis and secretion by the thyroid (242,332), increased D1 and D2 activities in the thyroid and D2 activity in BAT (334,335), low T 4 in plasma and tissues (71,336,337), and a TSH concentration that is slightly elevated, together with a normal or slightly decreased T 3 level in serum and several tissues (71). Tissue uptake of T 4 and T 3 increases.…”

Section: [G1] Iodine Deficiency In Rodentsmentioning

confidence: 99%

American Thyroid Association Guide to Investigating Thyroid Hormone Economy and Action in Rodent and Cell Models

Bianco

Anderson

Forrest

et al. 2014

Thyroid

174

106

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Section: [G1] Iodine Deficiency In Rodentsmentioning

confidence: 99%

American Thyroid Association Guide to Investigating Thyroid Hormone Economy and Action in Rodent and Cell Models

Bianco

Anderson

Forrest

et al. 2014

Thyroid

174

106

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“…Briefly, the total volume of the reaction mixture was 100·l and contained 1·nmol·l ) was calculated as previously described (Pazos-Moura et al, 1991). Protein content was measured by the Bradford method.…”

Section: Deiodination Assaymentioning

confidence: 99%

Functional identification of an osmotic response element (ORE) in the promoter region of the killifish deiodinase 2 gene (FhDio2)

López-Bojórquez

Villalobos

Garcı́a-G

et al. 2007

Journal of Experimental Biology

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SUMMARY The physiological role played by thyroid hormones (TH) in hydro-osmotic homeostasis in fish remains a controversial issue. Previous studies have shown that in Fundulus heteroclitus (killifish) hypo-osmotic stress increases liver iodothyronine deiodinase type 2 (D2) mRNA and D2 activity. In this study we identified two conserved osmotic response element (ORE) motifs in the promoter region of the killifish D2 gene (FhDio2) and examined their possible role in the transcriptional regulation of FhDio2during hypo-osmotic stress. As assessed by the electrophoretic mobility shift assay, results from in vivo and in vitro experiments demonstrate that exposure to an abrupt hyposmotic challenge triggers in the liver of killifish a strong nuclear recruitment of a putative osmotic response element binding protein (OREBP). This protein–DNA binding is time-dependent, attains a maximum within 2–8 h after the osmotic stress,and is followed by a significant increase in D2 activity. Furthermore,protein–DNA binding and the subsequent elevation in enzyme activity were blocked by the tyrosine kinase inhibitor genistein. Thus, during hypo-osmotic stress, a putative OREBP kinase-activated pathway stimulates FhDio2transcription and enzymatic activity. These data and the fact that D2 is the major enzyme providing local intracellular T3 suggest that TH plays a direct role in osmoregulation in fish, possibly by participating in hepatic ammonia metabolism. This study provides important insight into the physiological role of TH in hydro-osmotic homeostasis in fish.

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“…Thyroid, pituitary, liver, muscle and BAT deiodinase activities were measured based on methods previously described (Pazos- Moura et al 1991, Lisboa et al 2001 and, for mammary deiodinase activities, we used protocols described previously (Aceves & Valverde 1989, Song et al 2000, with slight modifications. D1 and D2 assays were performed in phosphate buffer containing 1 mM EDTA, pH 6·9.…”

Section: Deiodinase Activity Measurementmentioning

confidence: 99%

Increased 5'-iodothyronine deiodinase activity is a maternal adaptive mechanism in response to protein restriction during lactation

Lisboa¹,

Passos²,

Dutra³

et al. 2003

Journal of Endocrinology

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We have shown that protein restriction during lactation is associated with higher levels of serum and milk tri-iodothyronine (T 3 ) with lower serum thyroxine (T 4 ), suggesting an increased T 4 to T 3 conversion. To investigate this hypothesis, the activity of type 1 (D1) and/or type 2 (D2) iodothyronine deiodinases was evaluated on days 4, 12 and 21 of lactation in several tissues of dams fed an 8% protein-restricted (PR) diet and controls fed a 23% protein diet. Serum TSH, T 3 and T 4 were measured by radioimmunoassay. Deiodinase activity was determined by the release of 125 I from 125 I-reverse T 3 , under specific conditions for D1 or D2. PR dams had a transitory reduction in liver D1 activity (P<0·05) on day 12, and a small increase in thyroid D1 on day 12 followed by a small decrease on day 21. However, thyroid D2 activity was higher than controls (P<0·05) during the whole of the lactation period. Mammary gland D1 and D2 activities were lower on day 4 of lactation in PR dams (P<0·05), and D2 was higher on day 21 (P<0·05). Potentially, a lower conversion of T 3 to di-iodothyronine in the mammary glands of PR dams at the beginning of lactation may serve to provide more T 3 through the milk. Brown adipose tissue (BAT) D2 activity was higher (P<0·05) in PR dams during all periods of lactation. PR dams showed higher skeletal muscle D1 activity only at the end of lactation, but no changes in D2 activity. Higher pituitary D1 and D2 activities in the PR group (P<0·05) at the end of lactation could have contributed to the lower serum TSH. These data suggest that the higher thyroid and BAT D2 activity during the whole of lactation and skeletal muscle D1 activity at the end of lactation may contribute to the higher serum T 3 in PR dams.

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Effect of iodine deficiency and cold exposure on thyroxine 5'-deiodinase activity in various rat tissues

Cited by 44 publications

References 24 publications

American Thyroid Association Guide to Investigating Thyroid Hormone Economy and Action in Rodent and Cell Models

American Thyroid Association Guide to Investigating Thyroid Hormone Economy and Action in Rodent and Cell Models

Functional identification of an osmotic response element (ORE) in the promoter region of the killifish deiodinase 2 gene (FhDio2)

Increased 5'-iodothyronine deiodinase activity is a maternal adaptive mechanism in response to protein restriction during lactation

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