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Mol Cell Endocrinol. 2012 Nov 5;363(1-2):92-9. doi: 10.1016/j.mce.2012.07.012. Epub 2012 Aug 2.

Androgen receptor repression of gonadotropin-releasing hormone gene transcription via enhancer 1.

Author information

1
Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093-0674, USA.

Abstract

Gonadotropin-releasing hormone (GnRH) plays a major role in the hypothalamic-pituitary-gonadal (HPG) axis, and synthesis and secretion of GnRH are regulated by gonadal steroid hormones. Disruptions in androgen levels are involved in a number of reproductive defects, including hypogonadotropic hypogonadism and polycystic ovarian syndrome. Androgens down-regulate GnRH mRNA synthesis in vivo and in vitro via an androgen receptor (AR)-dependent mechanism. Methyltrienolone (R1881), a synthetic AR agonist, represses GnRH expression through multiple sites in the proximal promoter. In this study, we show AR also represses GnRH transcription via the major enhancer (GnRH-E1). A multimer of the -1800/-1766 region was repressed by R1881 treatment. Mutation of two bases, -1792 and -1791, resulted in decreased basal activity and a loss of AR-mediated repression. AR bound to the -1796/-1791 sequence in electrophoretic mobility shift assays, indicating a direct interaction with DNA or other transcription factors in this region. We conclude that AR repression of GnRH-E1 acts via multiple AR-responsive regions, including the site at -1792/-1791.

PMID:
22877652
PMCID:
PMC3447085
DOI:
10.1016/j.mce.2012.07.012
[Indexed for MEDLINE]
Free PMC Article

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