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Rapid regulation of thyroid sodium-iodide symporter activity by thyrotrophin and iodine.
J Endocrinol 2005; 184(1):69-76JE

Abstract

Transport of iodide into thyrocytes, a fundamental step in thyroid hormone biosynthesis, depends on the presence of the sodium-iodide symporter (NIS). The importance of the NIS for diagnosis and treatment of diseases has raised several questions about its physiological control. The goal of this study was to evaluate the influence of thyroid iodine content on NIS regulation by thyrotrophin (TSH) in vivo. We showed that 15-min thyroid radioiodine uptake can be a reliable measurement of NIS activity in vivo. The effect of TSH on the NIS was evaluated in rats treated with 1-methyl-2-mercaptoimidazole (MMI; hypothyroid with high serum TSH concentrations) for 21 days, and after 1 (R1d), 2 (R2d), or 5 (R5d) days of withdrawal of MMI. NIS activity was significantly greater in both MMI and R1d rats. In R2d and R5d groups, thyroid iodide uptake returned to normal values, despite continuing high serum TSH, possibly as a result of the re-establishment of iodine organification after withdrawal of MMI. Excess iodine (0.05% NaI for 6 days) promoted a significant reduction in thyroid radioiodide uptake, an effect that was blocked by concomitant administration of MMI, confirming previous findings that iodine organification is essential for the iodide transport blockade seen during iodine overload. Therefore, our data show that modulation of the thyroid NIS by TSH depends primarily on thyroid iodine content and, further, that the regulation of NIS activity is rapid.

Authors+Show Affiliations

Laboratório de Fisiologia Endócrina, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15642784

Citation

Ferreira, Andrea C F., et al. "Rapid Regulation of Thyroid Sodium-iodide Symporter Activity By Thyrotrophin and Iodine." The Journal of Endocrinology, vol. 184, no. 1, 2005, pp. 69-76.
Ferreira AC, Lima LP, Araújo RL, et al. Rapid regulation of thyroid sodium-iodide symporter activity by thyrotrophin and iodine. J Endocrinol. 2005;184(1):69-76.
Ferreira, A. C., Lima, L. P., Araújo, R. L., Müller, G., Rocha, R. P., Rosenthal, D., & Carvalho, D. P. (2005). Rapid regulation of thyroid sodium-iodide symporter activity by thyrotrophin and iodine. The Journal of Endocrinology, 184(1), pp. 69-76.
Ferreira AC, et al. Rapid Regulation of Thyroid Sodium-iodide Symporter Activity By Thyrotrophin and Iodine. J Endocrinol. 2005;184(1):69-76. PubMed PMID: 15642784.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Rapid regulation of thyroid sodium-iodide symporter activity by thyrotrophin and iodine. AU - Ferreira,Andrea C F, AU - Lima,Lívia P, AU - Araújo,Renata L, AU - Müller,Glaucia, AU - Rocha,Renata P, AU - Rosenthal,Doris, AU - Carvalho,Denise P, PY - 2005/1/12/pubmed PY - 2005/2/26/medline PY - 2005/1/12/entrez SP - 69 EP - 76 JF - The Journal of endocrinology JO - J. Endocrinol. VL - 184 IS - 1 N2 - Transport of iodide into thyrocytes, a fundamental step in thyroid hormone biosynthesis, depends on the presence of the sodium-iodide symporter (NIS). The importance of the NIS for diagnosis and treatment of diseases has raised several questions about its physiological control. The goal of this study was to evaluate the influence of thyroid iodine content on NIS regulation by thyrotrophin (TSH) in vivo. We showed that 15-min thyroid radioiodine uptake can be a reliable measurement of NIS activity in vivo. The effect of TSH on the NIS was evaluated in rats treated with 1-methyl-2-mercaptoimidazole (MMI; hypothyroid with high serum TSH concentrations) for 21 days, and after 1 (R1d), 2 (R2d), or 5 (R5d) days of withdrawal of MMI. NIS activity was significantly greater in both MMI and R1d rats. In R2d and R5d groups, thyroid iodide uptake returned to normal values, despite continuing high serum TSH, possibly as a result of the re-establishment of iodine organification after withdrawal of MMI. Excess iodine (0.05% NaI for 6 days) promoted a significant reduction in thyroid radioiodide uptake, an effect that was blocked by concomitant administration of MMI, confirming previous findings that iodine organification is essential for the iodide transport blockade seen during iodine overload. Therefore, our data show that modulation of the thyroid NIS by TSH depends primarily on thyroid iodine content and, further, that the regulation of NIS activity is rapid. SN - 0022-0795 UR - https://www.unboundmedicine.com/medline/citation/15642784/full_citation L2 - https://joe.bioscientifica.com/doi/10.1677/joe.1.05643 DB - PRIME DP - Unbound Medicine ER -