Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8463468 | Cell Calcium | 2012 | 9 Pages |
Abstract
The secretion of growth hormone (GH) from somatotrophs located within the anterior pituitary gland is stimulated by endogenous hypothalamic growth hormone-releasing hormone (GHRH) and the GH secretagogue (GHS) ghrelin, and inhibited by somatotropin-releasing inhibitory factor (SRIF, also known as somatostatin). These factors bind to specific G-protein-coupled receptors on the cell membrane, and directly or indirectly modify the properties of ion channels and second messenger systems. Ultimately this results in a change in intracellular free Ca2+ concentration ([Ca2+]i) and the secretion of GH. Somatotrophs possess a variety of ion channels on their membranes, and modification of these ion channels, especially Ca2+, K+, and Na+ channels, is tightly linked to intracellular Ca2+ levels and therefore hormone secretion. Various issues regarding receptor distribution, role of ion channels, alteration of membrane potential, and involvement of intracellular signaling system in the control of GH secretion are discussed in this review. In particular, this work will focus on ion channels and [Ca2+]i in somatotrophs.
Keywords
IGF-1TTX-STTX-RSSTRDHPGHS-RVGCCsGHSTTXSRIFGHRHLVATrpGH secretagoguecAMP[Ca2+]iCyclic adenosine monophosphateinsulin-like growth factor-1tetrodotoxinDihydropyridineSomatotrophintracellular free calcium concentrationArcNitric oxidearcuate nucleusperiventricular nucleusgrowth hormone-releasing hormoneGrowth hormonehigh-voltage activatedHVAvoltage-gated calcium channelsIon channelsLow-voltage activatedGhrelingrowth hormone secretagogue receptorSomatostatin receptor
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Authors
Seung-Kwon Yang, Frederik Steyn, Chen Chen,