Neuroscience 2004 Abstract
| Presentation Number: | 192.1 |
|---|---|
| Abstract Title: | The orphanin FQ receptor, opioid receptor like-1, is expressed in the GT1-7 cells and pituitary. |
| Authors: |
Foradori, C. D.*1
; Robert, H. J.1
1Dept Biomed Sci, Colorado State Univ, Fort Collins, CO |
| Primary Theme and Topics |
Homeostatic and Neuroendocrine Systems - Neuroendocrine -- HPG axis regulation |
| Session: |
192. Gonadotropin Secretion: Pharmacology Poster |
| Presentation Time: | Sunday, October 24, 2004 8:00 AM-9:00 AM |
| Location: | San Diego Convention Center - Hall A-H, Board # BB11 |
| Keywords: | reproduction, opioid, GnRH, LHRH |
Secretion of gonadotropin-releasing hormone (GnRH) is the final common pathway for the neuroendocrine control of reproduction. The factors regulating GnRH release are poorly understood. Recently, it was discovered that the peptide orphanin FQ (OFQ), also known as nociceptin, is found in a high percentage of GnRH neurons (Foradori et al.,abstract SFN 2003) and that OFQ can reduce GnRH release in vitro (Dhandapani and Brann, 2002). This suggests that OFQ plays a previously undisclosed role in controlling GnRH activity and/or can be secreted from the hypothalamus to affect anterior pituitary function. Thus, to study the direct effects of OFQ on GnRH cells and to explore mechanisms for possible downstream neuroendocrine effects of OFQ we have begun to examine the distribution of the OFQ receptor, opioid receptor like-1 (ORL-1) in brain and pituitary and in a GnRH secreting cell line, GT1-7. GT1-7 cells have proven to be the cell line with characteristics most similar to endogenous GnRH neurons. Therefore, we were interested in the possible presence of the OFQ and its receptor ORL-1 in this cell line. OFQ was identified using immunocytochemistry and RT-PCR was used to identify the presence of OFQ and ORL-1 mRNA. Similar to endogenous GnRH cells, all GT1-7 cells were OFQ immunoreactive. RT-PCR results demonstrate that GT1-7 cells express OFQ and ORL-1 mRNAs. The presence of OFQ mRNA and peptide in GT1 cells suggests that expression of OFQ in GnRH neurons is highly conserved. The presence of OFQ nerve terminals in the external zone of the median eminence would suggest that it is released into the portal vasculature and enters the anterior pituitary. Therefore, to determine if OFQ could have a direct effect on the pituitary, the presence of ORL-1 in pituitary was examined. RT-PCR showed that ORL-1 mRNA is present in the rat pituitary, thus establishing this link. Nonetheless, it remains to be determined which cell phenotype is expressing ORL-1 mRNA.
Supported by T32 NS43115
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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