Iodine excess exposure during pregnancy and lactation impairs maternal thyroid function in rats

Autor(es)

Serrano-Nascimento, Caroline ; Salgueiro, Rafael Barrera ; Vitzel, Kaio Fernando ; Pantaleao, Thiago ; Correa da Costa, Vania Maria ; Nunes, Maria Tereza

• Tipo de documento: Artigo Científico
• Fonte: ENDOCRINE CONNECTIONS; v. 6, n. 7, p. 12-pg., 2017-10-01.

Resumo

Adequate maternal iodine consumption during pregnancy and lactation guarantees normal thyroid hormones (TH) production, which is crucial to the development of the fetus. Indeed, iodine deficiency is clearly related to maternal hypothyroidism and deleterious effects in the fetal development. Conversely, the effects of iodine excess (IE) consumption on maternal thyroid function are still controversial. Therefore, this study aimed to investigate the impact of IE exposure during pregnancy and lactation periods on maternal hypothalamus-pituitary-thyroid axis. IE-exposed dams presented reduced serum TH concentration and increased serum thyrotropin (TSH) levels. Moreover, maternal IE exposure increased the hypothalamic expression of Trh and the pituitary expression of Trhr, Dio2, Tsha and Tshb mRNA, while reduced the Gh mRNA content. Additionally, IE-exposed dams presented thyroid morphological alterations, increased thyroid oxidative stress and decreased expression of thyroid genes/proteins involved in TH synthesis, secretion and metabolism. Furthermore, Dio1 mRNA expression and D1 activity were reduced in the liver and the kidney of IE-treated animals. Finally, the mRNA expression of Slc5a5 and Slc26a4 were reduced in the mammary gland of IE-exposed rats. The latter results are in accordance with the reduction of prolactin expression and serum levels in IE-treated dams. In summary, our study indicates that the exposure to IE during pregnancy and lactation induces primary hypothyroidism in rat dams and impairs iodide transfer to the milk. (AU)

• Processo FAPESP: 13/05629-4 - Ações genômicas vs não genômicas dos hormônios tiroidianos: mudanças de paradigmas, implicações fisiológicas e perspectivas terapêuticas
• Beneficiário: Maria Tereza Nunes
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 12/24391-6 - Impacto da exposição ao excesso de iodo durante a prenhez e/ou lactação sobre a atividade do eixo hipotálamo-hipófise-tireoide materno e da prole
• Beneficiário: Caroline Serrano Do Nascimento
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado