T3 differentially regulates TRH expression in developing hypothalamic neurons in vitro.
Triiodothyronine (T3) plays an important role during development of the central nervous system. T3 effects on gene expression are determined in part by the type of thyroid hormone receptors (TRs) expressed in a given cell type. Previous studies have demonstrated that thyrotropin releasing hormone (TRH) transcription in the adult hypothalamus is subjected to negative regulation by thyroid hormones. However, the role of T3 on the development of TRH expression is unknown. In this study we used primary cultures derived from 17-day-old fetal rat hypothalamus to analyze the effects of T3 on TRH gene expression during development. T3 increased TRH mRNA expression in immature cultures, but decreased it in mature cultures. In addition, T3 up-regulated TRalpha1 and TRbeta2 mRNA expression. TRalpha1 expression coincided chronologically with that of TRH in the rat hypothalamus in vivo. Maturation of TRH expression in the hypothalamus may involve T3 acting through TRalpha1.
Carreón-Rodríguez
Alfonso
A
Departamento de Genética y Fisiología Molecular, Instituto de Biotecnología, UNAM, A.P. 510-3, Cuernavaca, Morelos 62271, Mexico.
Charli
Jean-Louis
JL
Pérez-Martínez
Leonor
L
D000367:Age Factors; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D015870:Gene Expression / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D037021:Thyroid Hormone Receptors alpha / Q000235:genetics / Q000378:metabolism; D037042:Thyroid Hormone Receptors beta / Q000235:genetics / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014284:Triiodothyronine / Q000378:metabolism* / Q000494:pharmacology; D015854:Up-Regulation
D012333:RNA, Messenger; D037021:Thyroid Hormone Receptors alpha; D037042:Thyroid Hormone Receptors beta; D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone