Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain

11 pages, 5 figures, 1 table, 1 appendix.

Detalles Bibliográficos
Autores: Calvo, Rosa M., Obregón, María Jesús, Ruiz de Oña, Carmen, Escobar del Rey, Francisco, Morreale de Escobar, Gabriella
Tipo de recurso: artículo
Fecha de publicación:1990
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/23785
Acceso en línea:http://hdl.handle.net/10261/23785
Access Level:acceso abierto
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spelling Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brainCalvo, Rosa M.Obregón, María JesúsRuiz de Oña, CarmenEscobar del Rey, FranciscoMorreale de Escobar, Gabriella11 pages, 5 figures, 1 table, 1 appendix.To study the protective effects of maternal thyroxine (T4) and 3,5,3'-triiodothyronine (T3) in congenital hypothyroidism, we gave pregnant rats methimazole (MMI), an antithyroid drug that crosses the placenta, and infused them with three different doses of T4 or T3. The concentrations of both T4 and T3 were determined in maternal and fetal plasma and tissues (obtained near term) by specific RIAs. Several thyroid hormone-dependent biological end-points were also measured. MMI treatment resulted in marked fetal T4 and T3 deficiency. Infusion of T4 into the mothers increased both these pools in a dose-dependent fashion. There was a preferential increase of T3 in the fetal brain. Thus, with a T4 dose maintaining maternal euthyroidism, fetal brain T3 reached normal values, although fetal plasma T4 was 40% of normal and plasma TSH was high. The infusion of T3 pool into the mothers increased the total fetal extrathyroidal T3 pool in a dose-dependent fashion. The fetal T4 pools were not increased, however, and this deprived the fetal brain (and possibly the pituitary) of local generation of T3 from T4. As a consequence, fetal brain T3 deficiency was not mitigated even when dams were infused with a toxic dose of T3. The results show that (a) there is a preferential protection of the brain of the hypothyroid fetus from T3 deficiency; (b) maternal T4, but not T3, plays a crucial role in this protection, and (c) any condition which lowers maternal T4 (including treatment with T3) is potentially harmful for the brain of a hypothyroid fetus. Recent confirmation of transplacental passage of T4 in women at term suggests that present results are relevant for human fetuses with impairment of thyroid function. Finding signs of hypothyroidism at birth does not necessarily mean that the brain was unprotected in utero, provided maternal T4 is normal. It is crucial to realize that maintainance of maternal "euthyroidism" is not sufficient, as despite hypothyroxinemia, the mothers may be clinically euthyroid if their T3 levels are normal.This work was carried out under grant PM 88-0005 from Dirección General Interministerial de Ciencia y Tecnologia (Spain).Peer reviewedAmerican Society for Clinical Investigation201020101990info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_65012742691 bytesapplication/pdfhttp://hdl.handle.net/10261/23785reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1172/JCI114790info:eu-repo/semantics/openAccessoai:digital.csic.es:10261/237852026-05-22T06:33:51Z
dc.title.none.fl_str_mv Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
title Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
spellingShingle Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
Calvo, Rosa M.
title_short Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
title_full Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
title_fullStr Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
title_full_unstemmed Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
title_sort Congenital hypothyroidism, as studied in rats. Crucial role of maternal thyroxine but not of 3,5,3'-triiodothyronine in the protection of the fetal brain
dc.creator.none.fl_str_mv Calvo, Rosa M.
Obregón, María Jesús
Ruiz de Oña, Carmen
Escobar del Rey, Francisco
Morreale de Escobar, Gabriella
author Calvo, Rosa M.
author_facet Calvo, Rosa M.
Obregón, María Jesús
Ruiz de Oña, Carmen
Escobar del Rey, Francisco
Morreale de Escobar, Gabriella
author_role author
author2 Obregón, María Jesús
Ruiz de Oña, Carmen
Escobar del Rey, Francisco
Morreale de Escobar, Gabriella
author2_role author
author
author
author
description 11 pages, 5 figures, 1 table, 1 appendix.
publishDate 1990
dc.date.none.fl_str_mv 1990
2010
2010
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/23785
url http://hdl.handle.net/10261/23785
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.1172/JCI114790
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 2742691 bytes
application/pdf
dc.publisher.none.fl_str_mv American Society for Clinical Investigation
publisher.none.fl_str_mv American Society for Clinical Investigation
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,81155

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