title: Retinoic acid effects on thyroid function of female rats.
abstract: OBJECTIVE
  Retinoic acid is widely used in dermatological treatment and thyroid cancer management; however its possible side-effects on normal thyroid function remains unknown. We aimed to determine the effects of retinoic acid on thyroid function of adult female rats.
  
  
  METHODS
  Female Wistar rats were treated with all-trans-retinoic acid and 13-cis retinoic acid for 14 and 28 days. Then, rats were killed and thyroid function was evaluated.
  
  
  RESULTS
  Serum T4 and thyrotropin levels remained unchanged, while serum T3 increased in animals treated with all-trans-retinoic acid for 14 days. No changes were observed in hepatic or renal type 1 iodothyronine deiodinase (D1) activities, while thyroid D1 was higher in animals treated for 14 days with all-trans-retinoic acid, which could be related to the increased serum T3 levels. 13-cis retinoic acid increased thyroid iodide uptake after 28 days. These results show effects of retinoic acid treatment on these thyroid proteins: sodium/iodide symporter and deiodinase.
  
  
  CONCLUSIONS
  Retinoic acid is able to interfere with normal thyroid function, increasing thyroid type 1 deiodinase activity, serum T3 levels and sodium/iodide symporter function. However, the effects are time- and retinoic acid isomer-dependent. Since serum thyrotropin levels did not change in any group, the effects observed are probably mediated by a direct retinoic acid effect on the normal thyroid.
authors.affiliation: Laboratório de Fisiologia Endócrina from Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Alba Cenélia M
authors.initials: AC
authors.lastname: Silva
authors.forename: Michelle Porto
authors.initials: MP
authors.lastname: Marassi
authors.forename: Mônica
authors.initials: M
authors.lastname: Mühlbauer
authors.forename: Alexandre L
authors.initials: AL
authors.lastname: Lourenço
authors.forename: Denise P
authors.initials: DP
authors.lastname: Carvalho
authors.forename: Andrea C F
authors.initials: AC
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D005260:Female; D007453:Iodide Peroxidase / Q000378:metabolism; D007457:Iodine Radioisotopes / Q000378:metabolism; D007641:Keratolytic Agents / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D027981:Symporters / Q000378:metabolism; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism; D014212:Tretinoin / Q000737:chemistry / Q000494:pharmacology*; D014284:Triiodothyronine / Q000097:blood; D000099209:Sodium-Iodide Symporters
chemical_list: D007453:Iodide Peroxidase; D007457:Iodine Radioisotopes; D007641:Keratolytic Agents; D027981:Symporters; D014212:Tretinoin; D014284:Triiodothyronine; D000099209:Sodium-Iodide Symporters; C109812:iodothyronine deiodinase type I