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dc.contributor.authorSteiner, Robert A.en_US
dc.contributor.authorClifton, Donald K.en_US
dc.contributor.authorRossmanith, Winfried G.en_US
dc.contributor.authorMarks, Daniel L.en_US
dc.date.accessioned2008-10-17T20:40:43Z
dc.date.available2008-10-17T20:40:43Z
dc.date.issued1994-10en_US
dc.identifier.citationEndocrinology. 1994 Oct;135(4):1401-8en_US
dc.identifier.urihttp://hdl.handle.net/1773/4320
dc.description.abstractThe onset of puberty reflects the developmental activation of GnRH neurons whose secretory activity awakens the reproductive axis; however, the cellular mechanisms involved in this activational process remain poorly understood. GnRH neurons coexpress the neuropeptide galanin, and we have previously shown that galanin's level of coexpression is linked to the activity state of GnRH neurons. We theorized that altered expression of galanin by GnRH neurons may be an important mechanism related to activation of GnRH neurons at puberty. We examined two hypotheses related to this idea. First, we tested the hypothesis that expression of galanin messenger RNA (mRNA) in GnRH neurons is induced across the transition from prepubertal to adult life in the rat. To accomplish this, we used double label in situ hybridization and image analysis to compare cellular levels of galanin mRNA in GnRH neurons between groups of prepubertal and adult male and female rats. Levels of galanin mRNA within GnRH neurons increased significantly across puberty in both sexes. In females, galanin mRNA signal in GnRH neurons increased approximately 8-fold, whereas in males, cellular galanin mRNA signal levels increased about 2-fold. The number of identifiable GnRH neurons was not significantly different among the experimental groups. Next, we examined the hypothesis that pubertal induction of galanin mRNA in GnRH neurons reflects the activational effects of gonadal hormones associated with the onset of puberty. To test this, we killed groups of prepubertal male and female rats together with adult male and female animals that had been either castrated or sham castrated at a prepubertal age. In animals that had been prepubertally castrated, no developmental increase in galanin mRNA in GnRH neurons was observed, whereas in sham-castrated animals, levels of galanin mRNA in GnRH neurons were again shown to be higher in adult compared to prepubertal animals of both sexes, as had been demonstrated in the first experiment. We conclude that galanin message expression in GnRH neurons is induced during the transition from the juvenile to the adult state through a gonad-dependent process. This developmental increase in galanin gene expression is one mechanism by which the capacity for the synthesis and secretion of galanin by GnRH neurons may be enhanced, which, in turn, could facilitate the functional activity of GnRH neurons and amplify their trophic effect on the pituitary.en_US
dc.language.isoen_USen_US
dc.publisherEndocrine Societyen_US
dc.subjectgalaninen_US
dc.subjectGnRH neuronsen_US
dc.subjectpubertyen_US
dc.subjectsecretionen_US
dc.subject.meshNeurons, chemistry, physiologyen_US
dc.subject.meshMaleen_US
dc.subject.meshPeptides, analysis, geneticsen_US
dc.subject.meshRatsen_US
dc.subject.meshOrchiectomyen_US
dc.subject.meshAnimalsen_US
dc.subject.meshGalaninen_US
dc.subject.meshSexual Maturation, physiologyen_US
dc.subject.meshRats, Sprague-Dawleyen_US
dc.subject.meshResearch Support, Non-U.S. Gov'ten_US
dc.subject.meshComparative Studyen_US
dc.subject.meshRNA, Messenger, analysis, geneticsen_US
dc.subject.meshGonadorelin, analysis, geneticsen_US
dc.subject.meshIn Situ Hybridizationen_US
dc.subject.meshGene Expression Regulationen_US
dc.subject.meshResearch Support, U.S. Gov't, P.H.S.en_US
dc.subject.meshEstradiol, blooden_US
dc.subject.meshFemaleen_US
dc.subject.meshTestosterone, blooden_US
dc.titleInduction of galanin gene expression in gonadotropin-releasing hormone neurons with puberty in the raten_US
dc.typeArticleen_US


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