title: Estradiol decreases iodide uptake by rat thyroid follicular FRTL-5 cells.
abstract: Estradiol has well-known indirect effects on the thyroid. A direct effect of estradiol on thyroid follicular cells, increasing cell growth and reducing the expression of the sodium-iodide symporter gene, has been recently reported. The aim of the present investigation was to study the effect of estradiol on iodide uptake by thyroid follicular cells, using FRTL-5 cells as a model. Estradiol decreased basal iodide uptake by FRTL-5 cells from control levels of 2.490 +/- 0.370 to 2.085 +/- 0.364 pmol I-/microg DNA at 1 ng/ml (P<0.02), to 1.970 +/- 0.302 pmol I-/microg DNA at 10 ng/ml (P<0.003), and to 2.038 +/- 0.389 pmol I-/microg DNA at 100 ng/ml (P<0.02). In addition, 4 ng/ml estradiol decreased iodide uptake induced by 0.02 mIU/ml thyrotropin from 8.678 +/- 0.408 to 7.312 +/- 0.506 pmol I-/microg DNA (P<0.02). A decrease in iodide uptake by thyroid cells caused by estradiol has not been described previously and may have a role in goiter pathogenesis.
authors.affiliation: Divisão de Medicina Interna, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil. furlanet@cpovo.net
authors.forename: T W
authors.initials: TW
authors.lastname: Furlanetto
authors.forename: R B
authors.initials: RB
authors.lastname: Nunes
authors.forename: A M
authors.initials: AM
authors.lastname: Sopelsa
authors.forename: R M
authors.initials: RM
authors.lastname: Maciel
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology*; D007454:Iodides / Q000378:metabolism*; D051381:Rats; D018709:Statistics, Nonparametric; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013972:Thyrotropin / Q000494:pharmacology*
chemical_list: D007454:Iodides; D004958:Estradiol; D013972:Thyrotropin