Glucocorticoids stimulate TRH and c-fos/c-jun gene co-expression in cultured hypothalamic neurons.
To explore whether the protooncogenes, c-fos/c-jun, might be involved in regulating the effect of glucocorticoids on thyrotropin-releasing hormone in fetal rat diencephalic neurons, their localization and transcriptional activity were investigated using double-labeled in situ hybridization, Northern blot and nuclear run-on assays. The results showed that TRH mRNA was coexpressed with both c-jun and c-fos in the same neurons. Treatment with dexamethasone, a synthetic glucocorticoid, at 10(-8) M, enhanced transcriptional activity resulting in an increase in both cell number and intensity of all three mRNAs. The existence of c-fos/c-jun in thyrotropin-releasing hormone neurons and the increased transcriptional activity following dexamethasone treatment suggests that these protooncogenes could mediate the effect of glucocorticoids on thyrotropin-releasing hormone gene expression.
Luo
L G
LG
Division of Endocrinology, Brown University School of Medicine, Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903, USA.
Jackson
I M
IM
D000818:Animals; D015152:Blotting, Northern; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D016762:Genes, fos; D016758:Genes, jun; D005938:Glucocorticoids / Q000494:pharmacology*; D007031:Hypothalamus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D017403:In Situ Hybridization; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D013268:Stimulation, Chemical; D013973:Thyrotropin-Releasing Hormone / Q000235:genetics*
D005938:Glucocorticoids; D013973:Thyrotropin-Releasing Hormone; D003907:Dexamethasone