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Conference Paper: Biological basis and possible physiological implications of melatonin receptor-mediated signaling in the rat epididymis

TitleBiological basis and possible physiological implications of melatonin receptor-mediated signaling in the rat epididymis
Authors
KeywordsCAMP
Cell cycle
Epididymis
Epithelial cell
Receptors
Steroid hormones
Issue Date2000
PublisherS Karger AG. The Journal's web site is located at http://www.karger.com/NSG
Citation
International Symposium on Receptor and Non-Receptor Mediated Actions of Melatonin, Hong Kong, People's Republic of China, 06-08 November 1999. In Biological Signals And Receptors, 2000, v. 9 n. 3-4, p. 172-187 How to Cite?
AbstractThe mammalian epididymis plays an important role in sperm maturation, an important process of male reproduction. Specific high-affinity 2- [125I]iodomelatonin binding sites, satisfying the pharmacokinetic properties of specific receptors, have been found in the rat corpus epididymis, suggesting a direct melatonin action on epididymal physiology. Subsequent molecular and cell biology studies have identified these 2-[125I]iodomelatonin binding sites to be mt1 (MEL(1A)) and MT2 (MEL(1B)) melatonin receptor subtypes. Changes in the binding characteristics of these receptors in the rat corpus epididymis in response to castration and steroid hormones like testosterone and hydrocortisone indicated that these membrane melatonin receptors are biologically functional receptors, whose activities are differentially regulated by testosterone and hydrocortisone. These melatonin receptors are coupled to pertussis toxin (PTX)-sensitive G(i) protein and probably participate in androgenic and adrenergic regulation of rat corpus epididymal epithelial cell functions. Furthermore, rat corpus epididymal epithelial cell proliferation was stimulated by melatonin, whose action was dependent on the concentration and duration of exposure to the hormone. Interestingly, an MT2 receptor ligand (4- phenyl-2-propionamidotetraline, 4-P-PDOT) induced a stimulatory effect on epididymal epithelial cell proliferation similar to that produced by melatonin. In contrast, a nuclear melatonin receptor agonist (1-[3-allyl-4-oxo- thiazolidine-2-ylidene]-4-methyl-thiosemi-carbazone, CGP52608) and 8-bromo-cAMP inhibited epididymal epithelial cell proliferation. Taken together, our data lead us to postulate that one of the possible physiological functions of melatonin on the rate epididymis is the stimulation of mt1 and MT2 melatonin receptors resulting in the inhibition of cAMP signaling and an increase in epithelial cell proliferation. Copyright (C) 2000 S. Karger AG, Basel.
Persistent Identifierhttp://hdl.handle.net/10722/81338
ISSN
2003 Impact Factor: 3.5
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorShiu, SYWen_HK
dc.contributor.authorLi, Len_HK
dc.contributor.authorSiu, SWFen_HK
dc.contributor.authorXi, SCen_HK
dc.contributor.authorFong, SWen_HK
dc.contributor.authorPang, SFen_HK
dc.date.accessioned2010-09-06T08:16:31Z-
dc.date.available2010-09-06T08:16:31Z-
dc.date.issued2000en_HK
dc.identifier.citationInternational Symposium on Receptor and Non-Receptor Mediated Actions of Melatonin, Hong Kong, People's Republic of China, 06-08 November 1999. In Biological Signals And Receptors, 2000, v. 9 n. 3-4, p. 172-187en_HK
dc.identifier.issn1422-4933en_HK
dc.identifier.urihttp://hdl.handle.net/10722/81338-
dc.description.abstractThe mammalian epididymis plays an important role in sperm maturation, an important process of male reproduction. Specific high-affinity 2- [125I]iodomelatonin binding sites, satisfying the pharmacokinetic properties of specific receptors, have been found in the rat corpus epididymis, suggesting a direct melatonin action on epididymal physiology. Subsequent molecular and cell biology studies have identified these 2-[125I]iodomelatonin binding sites to be mt1 (MEL(1A)) and MT2 (MEL(1B)) melatonin receptor subtypes. Changes in the binding characteristics of these receptors in the rat corpus epididymis in response to castration and steroid hormones like testosterone and hydrocortisone indicated that these membrane melatonin receptors are biologically functional receptors, whose activities are differentially regulated by testosterone and hydrocortisone. These melatonin receptors are coupled to pertussis toxin (PTX)-sensitive G(i) protein and probably participate in androgenic and adrenergic regulation of rat corpus epididymal epithelial cell functions. Furthermore, rat corpus epididymal epithelial cell proliferation was stimulated by melatonin, whose action was dependent on the concentration and duration of exposure to the hormone. Interestingly, an MT2 receptor ligand (4- phenyl-2-propionamidotetraline, 4-P-PDOT) induced a stimulatory effect on epididymal epithelial cell proliferation similar to that produced by melatonin. In contrast, a nuclear melatonin receptor agonist (1-[3-allyl-4-oxo- thiazolidine-2-ylidene]-4-methyl-thiosemi-carbazone, CGP52608) and 8-bromo-cAMP inhibited epididymal epithelial cell proliferation. Taken together, our data lead us to postulate that one of the possible physiological functions of melatonin on the rate epididymis is the stimulation of mt1 and MT2 melatonin receptors resulting in the inhibition of cAMP signaling and an increase in epithelial cell proliferation. Copyright (C) 2000 S. Karger AG, Basel.en_HK
dc.languageengen_HK
dc.publisherS Karger AG. The Journal's web site is located at http://www.karger.com/NSGen_HK
dc.relation.ispartofBiological Signals and Receptorsen_HK
dc.rightsBiological Signals and Receptors. Copyright © S Karger AG.en_HK
dc.subjectCAMPen_HK
dc.subjectCell cycleen_HK
dc.subjectEpididymisen_HK
dc.subjectEpithelial cellen_HK
dc.subjectReceptorsen_HK
dc.subjectSteroid hormonesen_HK
dc.titleBiological basis and possible physiological implications of melatonin receptor-mediated signaling in the rat epididymisen_HK
dc.typeConference_Paperen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1422-4933&volume=9&spage=172&epage=187&date=2000&atitle=Biological+basis+and+possible+physiological+implications+of+melatonin+receptor-mediated+signaling+in+the+rat+epididymisen_HK
dc.identifier.emailShiu, SYW: sywshiu@hkucc.hku.hken_HK
dc.identifier.authorityShiu, SYW=rp00384en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1159/000014637-
dc.identifier.pmid10899702-
dc.identifier.scopuseid_2-s2.0-0033939837en_HK
dc.identifier.hkuros51403en_HK
dc.identifier.volume9en_HK
dc.identifier.issue3-4en_HK
dc.identifier.spage172en_HK
dc.identifier.epage187en_HK
dc.identifier.isiWOS:000088514000003-
dc.publisher.placeSwitzerlanden_HK
dc.description.otherInternational Symposium on Receptor and Non-Receptor Mediated Actions of Melatonin, Hong Kong, People's Republic of China, 06-08 November 1999. In Biological Signals And Receptors, 2000, v. 9 n. 3-4, p. 172-187-
dc.identifier.scopusauthoridShiu, SYW=7005550655en_HK
dc.identifier.scopusauthoridLi, L=36985948700en_HK
dc.identifier.scopusauthoridSiu, SWF=36905820000en_HK
dc.identifier.scopusauthoridXi, SC=35944696100en_HK
dc.identifier.scopusauthoridFong, SW=7102256321en_HK
dc.identifier.scopusauthoridPang, SF=7402528719en_HK
dc.customcontrol.immutablesml 160623 amended-

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