Retinoic acid decreases thyroid hormone receptor expression in pituitary GH1 cells.
Retinoic acid produced a time and dose-dependent depletion of thyroid hormone receptors in GH1 cells without modifying their affinity for triiodothyronine (T3). A maximal decrease (50-70%) was obtained after 24-48 h incubation with 5-10 microM retinoic acid. Treatment with 0.8 nM T3 for 24 h caused a similar reduction and did not potentiate the decrease produced by these concentrations of retinoic acid. However, the combination of sub-maximally effective doses of both ligands had an additive effect on receptor levels. The reduction of receptor caused by retinoic acid is accompanied by a decreased expression of c-erbA alpha 1 and alpha 2 mRNAs, but the retinoid did not reduce the abundance of c-erbA beta mRNA. In contrast, T3 decreased the levels of both alpha and beta transcripts.
Pérez
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P
Instituto de Investigaciones Biomédicas, CSIC, Madrid, Spain.
Sánchez-Pacheco
A
A
Pascual
A
A
Aranda
A
A
D000818:Animals; D002460:Cell Line; D005050:Etretinate / Q000494:pharmacology; D015474:Isotretinoin / Q000494:pharmacology; D007700:Kinetics; D046911:Macromolecular Substances; D010911:Pituitary Neoplasms; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D011988:Receptors, Thyroid Hormone / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology*; D014284:Triiodothyronine / Q000378:metabolism / Q000494:pharmacology; D014801:Vitamin A / Q000494:pharmacology
D046911:Macromolecular Substances; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine; D014801:Vitamin A; D011061:Poly A; D014212:Tretinoin; D012313:RNA; D005050:Etretinate; D015474:Isotretinoin