title: Short-term effects of triiodothyronine on thyroid hormone receptor alpha by PI3K pathway in adipocytes, 3T3-L1.
abstract: OBJECTIVE
  The present study aimed to examine the effects of thyroid hormone (TH), more precisely triiodothyronine (T3), on the modulation of TH receptor alpha (TRα) mRNA expression and the involvement of the phosphatidyl inositol 3 kinase (PI3K) signaling pathway in adipocytes, 3T3-L1, cell culture.
  
  
  METHODS
  It was examined the involvement of PI3K pathway in mediating T3 effects by treating 3T3-L1 adipocytes with physiological (P=10nM) or supraphysiological (SI =100 nM) T3 doses during one hour (short time), in the absence or the presence of PI3K inhibitor (LY294002). The absence of any treatment was considered the control group (C). RT-qPCR was used for mRNA expression analyzes. For data analyzes ANOVA complemented with Tukey's test was used at 5% significance level.
  
  
  RESULTS
  T3 increased TRα mRNA expression in P (1.91±0.13, p<0.001), SI (2.14±0.44, p<0.001) compared to C group (1±0.08). This increase was completely abrogated by LY294002 in P (0.53±0.03, p<0.001) and SI (0.31±0.03, p<0.001). To examine whether TRα is directly induced by T3, we used the translation inhibitor cycloheximide (CHX). The presence of CHX completely abrogated levels TRα mRNA in P (1.15±0.05, p>0.001) and SI (0.99±0.15, p>0.001), induced by T3.
  
  
  CONCLUSIONS
  These results demonstrate that the activation of the PI3K signaling pathway has a role in T3-mediated indirect TRα gene expression in 3T3-L1 adipocytes.
authors.affiliation: Department of Internal Medicine, Botucatu School of Medicine, University of São Paulo State, Botucatu, SP, Brazil.
authors.forename: Miriane de
authors.initials: Md
authors.lastname: Oliveira
authors.affiliation: Department of Internal Medicine, Botucatu School of Medicine, University of São Paulo State, Botucatu, SP, Brazil.
authors.forename: Regiane Marques Castro
authors.initials: RM
authors.lastname: Olimpio
authors.affiliation: Department of Internal Medicine, Botucatu School of Medicine, University of São Paulo State, Botucatu, SP, Brazil.
authors.forename: Maria Teresa De
authors.initials: MT
authors.lastname: Sibio
authors.affiliation: Department of Internal Medicine, Botucatu School of Medicine, University of São Paulo State, Botucatu, SP, Brazil.
authors.forename: Fernanda Cristina Fontes
authors.initials: FC
authors.lastname: Moretto
authors.affiliation: Institute of Health Sciences, Universidade Federal do Mato Grosso, Sinop, MT, Brazil.
authors.forename: Renata de Azevedo Mello
authors.initials: Rde A
authors.lastname: Luvizotto
authors.affiliation: Department of Internal Medicine, Botucatu School of Medicine, University of São Paulo State, Botucatu, SP, Brazil.
authors.forename: Célia Regina
authors.initials: CR
authors.lastname: Nogueira
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D002867:Chromones / Q000494:pharmacology; D015870:Gene Expression / Q000235:genetics; D018776:Genes, erbA / Q000187:drug effects; D051379:Mice; D009025:Morpholines / Q000494:pharmacology; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D037021:Thyroid Hormone Receptors alpha / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D002867:Chromones; D009025:Morpholines; D012333:RNA, Messenger; D037021:Thyroid Hormone Receptors alpha; D014284:Triiodothyronine; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D058539:Phosphatidylinositol 3-Kinase