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- PMID: 15821107
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Article: Paracrine regulation of growth hormone gene expression by gonadotrophin release in grass carp pituitary cells: Functional implications, molecular mechanisms and signal transduction
Title | Paracrine regulation of growth hormone gene expression by gonadotrophin release in grass carp pituitary cells: Functional implications, molecular mechanisms and signal transduction |
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Authors | |
Issue Date | 2005 |
Publisher | Society for Endocrinology. The Journal's web site is located at http://jme.endocrinology-journals.org/ |
Citation | Journal Of Molecular Endocrinology, 2005, v. 34 n. 2, p. 415-432 How to Cite? |
Abstract | Growth hormone (GH) is known to stimulate luteinizing hormone (LH) release via paracrine interactions between somatotrophs and gonadotrophs. However, it is unclear if LH can exert a reciprocal effect to modulate somatotroph functions. Here we examined the paracrine effects of LH on GH gene expression using grass carp pituitary cells as a cell model. LH receptors were identified in grass carp somatotrophs and their activation by human chorionic gonadotropin (hCG) increased 'steady-state' GH mRNA levels. Removal of endogenous LH by immunoneutralization using LH antiserum inhibited GH release and GH mRNA expression. GH secretagogues, including gonadotrophin releasing hormone (GnRH), pituitary adenylate cyclase-activating polypeptide (PACAP) and apomorphine, were effective in elevating GH mRNA levels but these stimulatory actions were blocked by LH antiserum. In pituitary cells pretreated with actinomycin D, the half-life of GH mRNA was not affected by hCG but was enhanced by LH immunoneutralization. Treatment with LH antiserum also suppressed basal levels of mature GH mRNA and primary transcripts. hCG increased cAMP synthesis in carp pituitary cells and hCG-induced GH mRNA expression was mimicked by forskolin but suppressed by inhibiting adenylate cyclase and protein kinase A. Similarly, the stimulatory actions of hCG and forskolin on GH mRNA expression were blocked by inhibiting Janus kinase 2 (JAK2) and MAP kinase (MAPK), including P42/44 MAPK and P38 MAPK. These results suggest that LH is essential for the maintenance of GH release, GH gene expression, and somatotroph responsiveness to GH-releasing factors. The paracrine actions of LH on GH mRNA expression are mediated by a concurrent increase in GH gene transcription and GH mRNA turnover, probably through JAK2/MAPK coupled to the cAMP-dependent pathway. © 2005 Society for Endocrinology. |
Persistent Identifier | http://hdl.handle.net/10722/178874 |
ISSN | 2023 Impact Factor: 3.6 2023 SCImago Journal Rankings: 1.243 |
ISI Accession Number ID | |
References |
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Zhou, H | en_US |
dc.contributor.author | Jiang, Y | en_US |
dc.contributor.author | Ko, WKW | en_US |
dc.contributor.author | Li, W | en_US |
dc.contributor.author | Wong, AOL | en_US |
dc.date.accessioned | 2012-12-19T09:50:19Z | - |
dc.date.available | 2012-12-19T09:50:19Z | - |
dc.date.issued | 2005 | en_US |
dc.identifier.citation | Journal Of Molecular Endocrinology, 2005, v. 34 n. 2, p. 415-432 | en_US |
dc.identifier.issn | 0952-5041 | en_US |
dc.identifier.uri | http://hdl.handle.net/10722/178874 | - |
dc.description.abstract | Growth hormone (GH) is known to stimulate luteinizing hormone (LH) release via paracrine interactions between somatotrophs and gonadotrophs. However, it is unclear if LH can exert a reciprocal effect to modulate somatotroph functions. Here we examined the paracrine effects of LH on GH gene expression using grass carp pituitary cells as a cell model. LH receptors were identified in grass carp somatotrophs and their activation by human chorionic gonadotropin (hCG) increased 'steady-state' GH mRNA levels. Removal of endogenous LH by immunoneutralization using LH antiserum inhibited GH release and GH mRNA expression. GH secretagogues, including gonadotrophin releasing hormone (GnRH), pituitary adenylate cyclase-activating polypeptide (PACAP) and apomorphine, were effective in elevating GH mRNA levels but these stimulatory actions were blocked by LH antiserum. In pituitary cells pretreated with actinomycin D, the half-life of GH mRNA was not affected by hCG but was enhanced by LH immunoneutralization. Treatment with LH antiserum also suppressed basal levels of mature GH mRNA and primary transcripts. hCG increased cAMP synthesis in carp pituitary cells and hCG-induced GH mRNA expression was mimicked by forskolin but suppressed by inhibiting adenylate cyclase and protein kinase A. Similarly, the stimulatory actions of hCG and forskolin on GH mRNA expression were blocked by inhibiting Janus kinase 2 (JAK2) and MAP kinase (MAPK), including P42/44 MAPK and P38 MAPK. These results suggest that LH is essential for the maintenance of GH release, GH gene expression, and somatotroph responsiveness to GH-releasing factors. The paracrine actions of LH on GH mRNA expression are mediated by a concurrent increase in GH gene transcription and GH mRNA turnover, probably through JAK2/MAPK coupled to the cAMP-dependent pathway. © 2005 Society for Endocrinology. | en_US |
dc.language | eng | en_US |
dc.publisher | Society for Endocrinology. The Journal's web site is located at http://jme.endocrinology-journals.org/ | en_US |
dc.relation.ispartof | Journal of Molecular Endocrinology | en_US |
dc.rights | Journal of Molecular Endocrinology. Copyright © Society for Endocrinology. | - |
dc.subject.mesh | Animals | en_US |
dc.subject.mesh | Antibodies, Monoclonal - Immunology | en_US |
dc.subject.mesh | Carps | en_US |
dc.subject.mesh | Cells, Cultured | en_US |
dc.subject.mesh | Chorionic Gonadotropin - Metabolism | en_US |
dc.subject.mesh | Dactinomycin - Metabolism | en_US |
dc.subject.mesh | Enzyme Inhibitors - Metabolism | en_US |
dc.subject.mesh | Gene Expression Regulation | en_US |
dc.subject.mesh | Growth Hormone - Genetics - Metabolism | en_US |
dc.subject.mesh | Humans | en_US |
dc.subject.mesh | Lasers | en_US |
dc.subject.mesh | Luteinizing Hormone - Immunology - Metabolism | en_US |
dc.subject.mesh | Mitogen-Activated Protein Kinases - Antagonists & Inhibitors - Metabolism | en_US |
dc.subject.mesh | Paracrine Communication | en_US |
dc.subject.mesh | Phosphatidylinositol 3-Kinases - Antagonists & Inhibitors - Metabolism | en_US |
dc.subject.mesh | Pituitary Gland - Cytology - Metabolism | en_US |
dc.subject.mesh | Promoter Regions, Genetic | en_US |
dc.subject.mesh | Protein Synthesis Inhibitors - Metabolism | en_US |
dc.subject.mesh | Rna, Messenger - Metabolism | en_US |
dc.subject.mesh | Receptors, Lh - Genetics - Metabolism | en_US |
dc.subject.mesh | Signal Transduction - Physiology | en_US |
dc.title | Paracrine regulation of growth hormone gene expression by gonadotrophin release in grass carp pituitary cells: Functional implications, molecular mechanisms and signal transduction | en_US |
dc.type | Article | en_US |
dc.identifier.email | Wong, AOL: olwong@hkucc.hku.hk | en_US |
dc.identifier.authority | Wong, AOL=rp00806 | en_US |
dc.description.nature | link_to_subscribed_fulltext | en_US |
dc.identifier.doi | 10.1677/jme.1.01629 | en_US |
dc.identifier.pmid | 15821107 | - |
dc.identifier.scopus | eid_2-s2.0-17844377065 | en_US |
dc.identifier.hkuros | 101436 | - |
dc.relation.references | http://www.scopus.com/mlt/select.url?eid=2-s2.0-17844377065&selection=ref&src=s&origin=recordpage | en_US |
dc.identifier.volume | 34 | en_US |
dc.identifier.issue | 2 | en_US |
dc.identifier.spage | 415 | en_US |
dc.identifier.epage | 432 | en_US |
dc.identifier.isi | WOS:000228583800012 | - |
dc.publisher.place | United Kingdom | en_US |
dc.identifier.scopusauthorid | Zhou, H=7404742310 | en_US |
dc.identifier.scopusauthorid | Jiang, Y=15061459000 | en_US |
dc.identifier.scopusauthorid | Ko, WKW=7202286890 | en_US |
dc.identifier.scopusauthorid | Li, W=36062301700 | en_US |
dc.identifier.scopusauthorid | Wong, AOL=7403147570 | en_US |
dc.identifier.issnl | 0952-5041 | - |