Estrogen regulation of gene expression in GnRH neurons

Yewade Ng, Andrew Wolfe, Horacio J. Novaira, Sally Radovick

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Estrogen plays an essential role in the regulation of the female reproductive hormone axis, and specifically is a major regulator of GnRH neuronal function in the female brain. GnRH neuronal cell lines were used to explore the direct effects of estradiol on gene expression in GnRH neurons. The presence of estrogen receptor (ER) binding sites was established by a receptor-binding assay, and estrogen receptor α and β mRNA were identified in GN11 cells and ERβ in GT1-7 cells using RT-PCR analysis of mRNA. ERα was more abundantly expressed in GN11 cells than ERβ as assessed by real-time PCR. Additionally, GN11 cells expressed significantly more of both ERα and β than GT1-7 cells. Functional studies in GN11 and GT1-7 demonstrated estrogen down regulation of endogenous mouse GnRH mRNA levels using quantitative real-time PCR (qRT-PCR). Correspondingly, estradiol also reduced secretion of GnRH from both the GN11 and GT1-7 cell lines. Since estradiol has been shown to regulate progesterone receptor (PR) expression; similar studies were performed demonstrating an estradiol mediated increase in PR in both cell lines. Estradiol regulation of ER expression was also explored and these studies indicated that estradiol decreased ERα and ERβ mRNA levels in a dose-dependent manner in GN11 and GT1-7 cells. These effects were blocked by the addition of the estrogen receptor antagonist ICI 182,780. Both PPT, a specific ERα agonist, and DPN, a specific ERβ agonist, inhibited GnRH gene expression in GN11 cells, but only DPN inhibited GnRH gene expression in GT1-7 cells, consistent with their undetectable levels of ERα expression. These studies characterize a direct inhibitory effect of estradiol on GnRH in GnRH neurons, and a direct stimulatory effect of estradiol on PR gene expression. In addition, the agonist studies indicate that there is a functional overlap of ERα and ERβ regulation in GnRH neurons. These studies may give insight into the molecular regulation of estrogen negative feedback in the central reproductive axis.

Original languageEnglish (US)
Pages (from-to)25-33
Number of pages9
JournalMolecular and Cellular Endocrinology
Volume303
Issue number1-2
DOIs
StatePublished - May 6 2009

Fingerprint

Gene Expression Regulation
Gene expression
Gonadotropin-Releasing Hormone
Estrogen Receptors
Neurons
Estrogens
Estradiol
Progesterone Receptors
Gene Expression
Messenger RNA
Cells
Cell Line
NAD
Real-Time Polymerase Chain Reaction
Assays
Brain
Down-Regulation
Binding Sites
Hormones
Feedback

All Science Journal Classification (ASJC) codes

  • Endocrinology
  • Molecular Biology
  • Biochemistry

Cite this

Ng, Yewade ; Wolfe, Andrew ; Novaira, Horacio J. ; Radovick, Sally. / Estrogen regulation of gene expression in GnRH neurons. In: Molecular and Cellular Endocrinology. 2009 ; Vol. 303, No. 1-2. pp. 25-33.
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Estrogen regulation of gene expression in GnRH neurons. / Ng, Yewade; Wolfe, Andrew; Novaira, Horacio J.; Radovick, Sally.

In: Molecular and Cellular Endocrinology, Vol. 303, No. 1-2, 06.05.2009, p. 25-33.

Research output: Contribution to journalArticle

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