Effects of α2- and β-adrenoceptor agonists on growth hormone secretion following lesion of the noradrenergic system of the rat

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dc.contributor.authorJaffer A.
dc.contributor.authorDaniels W.M.U.
dc.contributor.authorRussell V.A.
dc.contributor.authorTaljaard J.J.F.
dc.date.accessioned2011-05-15T16:17:27Z
dc.date.available2011-05-15T16:17:27Z
dc.date.issued1992
dc.description.abstractThe aim of the present investigation was to lesion the noradrenergic system and to measure the effect on growth hormone (GH) secretion following peripheral administration of α2- and β-adrenoceptor agonists. Direct injection of these agonists into the paraventricular nucleus of the hypothalamus (PVN) and its effect on GH secretion were also investigated. Systemic administration of N-2-chloroethyl-N-ethyl-2-bromobenzylamine (DSP4, 60 mg/kg, injected i.p. 10 days prior to experimentation) significantly decreased the noradrenaline (NA) content of the hippocampus, frontal cortex and hypothalamus but had no effect on the dopamine (DA) or serotonin (5-HT) content of these areas. Bilateral injection of 6-hydroxydopamine (6-OHDA, 10 μg/μl, 14 days prior to experimentation) into the medial forebrain bundle (MFB) caused a greater reduction of NA and also decreased the DA and 5-HT content of the hypothalamus. Analysis of the PVN of the hypothalami of rats following 6-OHDA lesion of the MFB showed significantly decreased NA and 5-HT content. Neither DSP4 treatment nor 6-OHDA lesion of the MFB affected the clonidine (250 μg/kg, i.p.) induced stimulation of GH secretion. Injection of isoproterenol (1 mg/kg, i.p.) had varying effects on GH secretion. It stimulated GH release in control rats but not in DSP4 or MFB lesioned rats. Direct injection of clonidine (0.1 μg/μl) into the PVN significantly stimulated GH secretion, whereas injection of isoproterenol (2.5 μg/μl) into the PVN did not affect GH levels when compared to controls. The results of the present study do not support the hypothesis that hypoactivity of the central noradrenergic system may be the cause of the blunted GH response to clonidine observed in depressed patients.
dc.description.versionArticle
dc.identifier.citationNeurochemical Research
dc.identifier.citation17
dc.identifier.citation12
dc.identifier.issn03643190
dc.identifier.other10.1007/BF00968409
dc.identifier.urihttp://hdl.handle.net/10019.1/14219
dc.subjectalpha 2 adrenergic receptor stimulating agent
dc.subjectbeta adrenergic receptor stimulating agent
dc.subjectclonidine
dc.subjectisoprenaline
dc.subjectnoradrenalin
dc.subjectoxidopamine
dc.subjectanimal tissue
dc.subjectarticle
dc.subjectbrain injury
dc.subjectcomparative study
dc.subjectcontrolled study
dc.subjectdopamine brain level
dc.subjectdrug effect
dc.subjectgrowth hormone blood level
dc.subjectgrowth hormone release
dc.subjecthippocampus
dc.subjectintraperitoneal drug administration
dc.subjectmale
dc.subjectmedial forebrain bundle
dc.subjectnonhuman
dc.subjectnoradrenalin brain level
dc.subjectnoradrenergic system
dc.subjectpriority journal
dc.subjectrat
dc.subjectserotonin brain level
dc.subjectthalamus midline nucleus
dc.subjectAdrenergic alpha-Agonists
dc.subjectAdrenergic beta-Agonists
dc.subjectAnimal
dc.subjectBenzylamines
dc.subjectClonidine
dc.subjectDopamine
dc.subjectFrontal Lobe
dc.subjectGrowth Hormone
dc.subjectHippocampus
dc.subjectHypothalamus
dc.subjectIsoproterenol
dc.subjectMale
dc.subjectMedial Forebrain Bundle
dc.subjectNorepinephrine
dc.subjectOxidopamine
dc.subjectParaventricular Hypothalamic Nucleus
dc.subjectRats
dc.subjectRats, Wistar
dc.subjectSerotonin
dc.subjectSupport, Non-U.S. Gov't
dc.subjectAnimalia
dc.titleEffects of α2- and β-adrenoceptor agonists on growth hormone secretion following lesion of the noradrenergic system of the rat
dc.typeArticle
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