Orphanin FQ and glutamate connection in the regulation of gonadotropin-releasing hormone secretion in the preoptic area of conscious male rats.
Utilizing the method of push-pull perfusion and radioimmunoassay (RIA), the secretory profile of gonadotropin-releasing hormone (GnRH) in the preoptic area (POA) and serum-luteinizing hormone (LH) levels were examined in conscious male rats after administration of [Nphe(1)]NC(1-13)NH(2), a competitive antagonists of the opioid receptor-like 1 receptor (ORL1 receptor) which is endogenous receptor for Orphanin FQ (OFQ). Glutamate release in the POA was also measured by high-performance liquid chromatography (HPLC) after perfusion of [Nphe(1)]NC(1-13)NH(2), i.e. NC13. The results showed that GnRH secretion from the POA and serum LH levels was increased significantly 40 min and 60 min, respectively after perfusion of 2 and 20 mmol/L NC13 in freely moving male rats (p<0.05). Pretreatment with a glutamate, N-methyl-D-aspartate (NMDA) receptor antagonist (MK-801, s.c., 0.2 mg/kg) abolished the increase of GnRH release in the POA induced by 2 mmol/L NC13. Additionally, 20 mmol/L NC13 significantly enhanced glutamate release in the POA at 40 min post-perfusion in a dose-dependent manner. These findings suggest that hypothalamic OFQ/ORL1 receptor system plays a role in the physiological inhibitory control of GnRH secretion in the POA of male rats, and provide evidence for involvement of an OFQ and glutamate pathway in the control of GnRH secretion.
Department of Endocrinology, Jiangsu Province Hospital of Traditional Chinese Medicine, 155 Han-Zhong Road, Nanjing 210029, PR China. anxiaofei2000@163.com
Xiao-Fei
XF
An
Yun-Fei
YF
Niu
Shi-Chao
SC
Ten
Jing-Shun
JS
Liu
Hao
H
Feng
Ming
M
He
Xiao-Jun
XJ
Shen
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D016291:Dizocilpine Maleate / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D018698:Glutamic Acid / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D008297:Male; D009292:Narcotic Antagonists; D018847:Opioid Peptides / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D011957:Receptors, Opioid / Q000819:agonists; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology; D000094942:Nociceptin Receptor; D000097629:Nociceptin
D016291:Dizocilpine Maleate; D018691:Excitatory Amino Acid Antagonists; D018698:Glutamic Acid; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D009292:Narcotic Antagonists; D018847:Opioid Peptides; D010446:Peptide Fragments; D016194:Receptors, N-Methyl-D-Aspartate; D011957:Receptors, Opioid; D014665:Vasodilator Agents; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C403776:nociceptin-(1-13)-NH2, NPhe(1)-; C000722285:Oprl1 protein, rat