RF-amide related peptide (RFRP) neurons lack the classical nuclear estrogen receptor-α but respond with reduced RFRP expression to estradiol

Abstract

Event Abstract Back to Event RF-amide related peptide (RFRP) neurons lack the classical nuclear estrogen receptor-α but respond with reduced RFRP expression to estradiol Csilla S. Molnár1, Zsolt Liposits1, Imre Kalló1 and Erik Hrabovszky1* 1 Institute of Experimental Medicine Hungarian Academy of Sciences, Laboratory of Endocrine Neurobiology, Hungary The RF-amide related peptides RFRP-1 and RFRP-3, derived from a common prepro-RFRP precursor, are synthesized in the dorsomedial hypothalamic nucleus (DMN) in mice. There is growing evidence for the crucial role of RFRPs in the central regulation of reproduction. RFRP-1 and RFRP-3 act via inhibiting gonadotropin-releasing hormone (GnRH) neurons of the preoptic area. To address if RFRP neurons are involved in estrogen signaling to GnRH cells, we first compared the expression of RFRP mRNA in ovariectomized mice with and without estradiol replacement. Quantitative in situ hybridization experiments established that a 4-day estradiol regimen caused the robust down-regulation of RFRP mRNA expression. Interneurons expressing the classic nuclear estrogen receptor (ER-α) play a crucial role in estrogen positive and negative feedback to GnRH neurons. Therefore, we addressed the presence of the classical nuclear ER-α in RFRP neurons with combined immunocytochemistry and in situ hybridization. Although ER-α was detectable in a subset of neurons in the DMN, the cell nuclei of RFRP neurons were consistently devoid of ER-α labeling. Next, we examined if the expression of the highly estrogen-dependent progesterone receptor (PR) can be induced by estradiol in RFRP neurons. RFRP neurons did not contain PR immunoreactivity in estradiol-treated mice. Finally, we studied and demonstrated RFRP-3 immunoreactivity in neuronal fibers that formed contacts with GnRH neurons. Results of these studies indicate that RFRP is an estradiol-regulated neurotransmitter. Estrogenic regulation of RFRP expression is likely indirect as RFRP neurons do not express detectable levels of ER-α and PR. The RFRP-3 immunoreactive neuronal contacts on GnRH neurons indicate that RFRP peptides may mediate estrogenic signals to GnRH neurons. This research was supported by the National Science Foundation of Hungary (OTKA K69127 and T73002). Conference: IBRO International Workshop 2010, Pécs, Hungary, 21 Jan - 23 Jan, 2010. Presentation Type: Poster Presentation Topic: Homeostatic and neuroendocrine systems Citation: Molnár CS, Liposits Z, Kalló I and Hrabovszky E (2010). RF-amide related peptide (RFRP) neurons lack the classical nuclear estrogen receptor-α but respond with reduced RFRP expression to estradiol. Front. Neurosci. Conference Abstract: IBRO International Workshop 2010. doi: 10.3389/conf.fnins.2010.10.00090 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Apr 2010; Published Online: 22 Apr 2010. * Correspondence: Erik Hrabovszky, Institute of Experimental Medicine Hungarian Academy of Sciences, Laboratory of Endocrine Neurobiology, Budapest, Hungary, hrabovszky.erik@koki.mta.hu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Csilla S Molnár Zsolt Liposits Imre Kalló Erik Hrabovszky Google Csilla S Molnár Zsolt Liposits Imre Kalló Erik Hrabovszky Google Scholar Csilla S Molnár Zsolt Liposits Imre Kalló Erik Hrabovszky PubMed Csilla S Molnár Zsolt Liposits Imre Kalló Erik Hrabovszky Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.