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Article: Differential actions of a mammalian gonadotropin-releasing hormone antagonist on gonadotropin-II and growth hormone release in goldfish, Carassius auratus

TitleDifferential actions of a mammalian gonadotropin-releasing hormone antagonist on gonadotropin-II and growth hormone release in goldfish, Carassius auratus
Authors
Issue Date1994
PublisherS Karger AG. The Journal's web site is located at http://www.karger.com/NEN
Citation
Neuroendocrinology, 1994, v. 59 n. 6, p. 561-571 How to Cite?
AbstractIn goldfish the two native forms of gonadotropin-releasing hormone (GnRH) salmon GnRH (sGnRH) and chicken GnRH-II (cGnRH-II), stimulate both gonadotropin-II (GTH-II) and growth hormone (GH) release. Modifications of GnRH structure at positions 1, 2, 3, and 6 often result in an antagonist in goldfish, an observation well documented in mammalian studies. In a preliminary study in goldfish, a mammalian GnRH antagonist, [Ac-D(2)Nal 1, 4Cl-D-Phe 2, D(3)-Pal 3,6, Arg 5, D-Ala 10]-mGnRH (analog L) weakly stimulated GTH-II release, and strongly inhibited GH release. The objectives of the present study were to study the dose-related actions of analog L on GTH-II and GH release in the goldfish, the specificity of inhibition of native GnRH actions, and to test whether analog L can act directly on goldfish pituitary cells. In a goldfish pituitary fragments perifusion system, analog L at different concentrations, given as 2-min pulses or as 30-min prolonged treatments, stimulated GTH-II and inhibited GH release in a dose-dependent manner. Analog L at 2 μM concentration (45 min) significantly suppressed sGnRH- and cGnRH-II-stimulated GTH-II as well as GH release. Analog L specifically inhibited GnRH-stimulated GH release, without having any significant effects on the GH release induced by either SKF38393, a dopamine D1 receptor agonist, or thyrotropin-releasing hormone. The GTH-II stimulatory and GH-inhibitory actions of analog L were significantly suppressed by a 'true' GnRH antagonist (Ac-Δ 3-Pro 1, 4FD-Phe 2, D-Trp 3,6)-mGnRH. Further, analog L stimulated GTH-II release and suppressed GH release from the enzymatically dispersed goldfish pituitary cells, indicating the direct actions of analog L at the pituitary cell level. Analog L also displaced 125I-(D-Arg 6, Pro 9 NHEt)-sGnRH bound to crude goldfish pituitary membrane preparations in a dose-related manner. In conclusion, contrary to its action as a potent GnRH antagonist in mammals, analog L has GTH-II stimulatory action in goldfish. Analog L by acting via GnRH receptors at the pituitary cell level differentially acts on GTH-II and GH release, suggesting functional differences in the properties of the GnRH receptors on GTH and GH cells. Analog L also specifically inhibits sGnRH and cGnRH-II actions on GTH-II and GH release.
Persistent Identifierhttp://hdl.handle.net/10722/178565
ISSN
2015 Impact Factor: 2.583
2015 SCImago Journal Rankings: 1.479
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorMurthy, CKen_US
dc.contributor.authorTurner, RJen_US
dc.contributor.authorWong, AOLen_US
dc.contributor.authorRao, PDPen_US
dc.contributor.authorRivier, JEen_US
dc.contributor.authorPeter, REen_US
dc.date.accessioned2012-12-19T09:48:24Z-
dc.date.available2012-12-19T09:48:24Z-
dc.date.issued1994en_US
dc.identifier.citationNeuroendocrinology, 1994, v. 59 n. 6, p. 561-571en_US
dc.identifier.issn0028-3835en_US
dc.identifier.urihttp://hdl.handle.net/10722/178565-
dc.description.abstractIn goldfish the two native forms of gonadotropin-releasing hormone (GnRH) salmon GnRH (sGnRH) and chicken GnRH-II (cGnRH-II), stimulate both gonadotropin-II (GTH-II) and growth hormone (GH) release. Modifications of GnRH structure at positions 1, 2, 3, and 6 often result in an antagonist in goldfish, an observation well documented in mammalian studies. In a preliminary study in goldfish, a mammalian GnRH antagonist, [Ac-D(2)Nal 1, 4Cl-D-Phe 2, D(3)-Pal 3,6, Arg 5, D-Ala 10]-mGnRH (analog L) weakly stimulated GTH-II release, and strongly inhibited GH release. The objectives of the present study were to study the dose-related actions of analog L on GTH-II and GH release in the goldfish, the specificity of inhibition of native GnRH actions, and to test whether analog L can act directly on goldfish pituitary cells. In a goldfish pituitary fragments perifusion system, analog L at different concentrations, given as 2-min pulses or as 30-min prolonged treatments, stimulated GTH-II and inhibited GH release in a dose-dependent manner. Analog L at 2 μM concentration (45 min) significantly suppressed sGnRH- and cGnRH-II-stimulated GTH-II as well as GH release. Analog L specifically inhibited GnRH-stimulated GH release, without having any significant effects on the GH release induced by either SKF38393, a dopamine D1 receptor agonist, or thyrotropin-releasing hormone. The GTH-II stimulatory and GH-inhibitory actions of analog L were significantly suppressed by a 'true' GnRH antagonist (Ac-Δ 3-Pro 1, 4FD-Phe 2, D-Trp 3,6)-mGnRH. Further, analog L stimulated GTH-II release and suppressed GH release from the enzymatically dispersed goldfish pituitary cells, indicating the direct actions of analog L at the pituitary cell level. Analog L also displaced 125I-(D-Arg 6, Pro 9 NHEt)-sGnRH bound to crude goldfish pituitary membrane preparations in a dose-related manner. In conclusion, contrary to its action as a potent GnRH antagonist in mammals, analog L has GTH-II stimulatory action in goldfish. Analog L by acting via GnRH receptors at the pituitary cell level differentially acts on GTH-II and GH release, suggesting functional differences in the properties of the GnRH receptors on GTH and GH cells. Analog L also specifically inhibits sGnRH and cGnRH-II actions on GTH-II and GH release.en_US
dc.languageengen_US
dc.publisherS Karger AG. The Journal's web site is located at http://www.karger.com/NENen_US
dc.relation.ispartofNeuroendocrinologyen_US
dc.rightsNeuroendocrinology. Copyright © S Karger AG.-
dc.subject.mesh2,3,4,5-Tetrahydro-7,8-Dihydroxy-1-Phenyl-1H-3-Benzazepine - Pharmacologyen_US
dc.subject.meshAnimalsen_US
dc.subject.meshFemaleen_US
dc.subject.meshGoldfishen_US
dc.subject.meshGonadotropin-Releasing Hormone - Analogs & Derivatives - Antagonists & Inhibitors - Metabolism - Pharmacologyen_US
dc.subject.meshGonadotropins, Pituitary - Metabolismen_US
dc.subject.meshGrowth Hormone - Metabolismen_US
dc.subject.meshMaleen_US
dc.subject.meshPituitary Gland - Drug Effects - Metabolismen_US
dc.subject.meshReceptors, Lhrh - Metabolismen_US
dc.titleDifferential actions of a mammalian gonadotropin-releasing hormone antagonist on gonadotropin-II and growth hormone release in goldfish, Carassius auratusen_US
dc.typeArticleen_US
dc.identifier.emailWong, AOL: olwong@hkucc.hku.hken_US
dc.identifier.authorityWong, AOL=rp00806en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1159/000126706-
dc.identifier.pmid8084380-
dc.identifier.scopuseid_2-s2.0-0028239705en_US
dc.identifier.hkuros5762-
dc.identifier.volume59en_US
dc.identifier.issue6en_US
dc.identifier.spage561en_US
dc.identifier.epage571en_US
dc.identifier.isiWOS:A1994NP94100007-
dc.publisher.placeSwitzerlanden_US
dc.identifier.scopusauthoridMurthy, CK=13309818400en_US
dc.identifier.scopusauthoridTurner, RJ=7404557239en_US
dc.identifier.scopusauthoridWong, AOL=7403147570en_US
dc.identifier.scopusauthoridRao, PDP=7404660629en_US
dc.identifier.scopusauthoridRivier, JE=35411857000en_US
dc.identifier.scopusauthoridPeter, RE=7202909690en_US

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