Differential involvement of signaling pathways in the regulation of growth hormone release by somatostatin and growth hormone-releasing hormone in orange-spotted grouper (Epinephelus coioides)

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• 作者：Bin Wang ; Chaobin Qin ; Cong Zhang ; Jirong Jia ; Caiyun Sun ; Wensheng Li
• 关键词：GH ; growth hormone ; SRIF ; somatotropin release-inhibitory factor ; GHRH ; GH-releasing hormone ; PACAP ; pituitary adenylate cyclase-activating peptide ; DA ; dopamine ; GnRH ; gonadotropin-releasing hormone ; GPCR ; G-protein-coupled receptor ; SSTR ; somatostatin receptor ; GHRH-R ; GHRH receptor ; PLC ; phospholipase C ; IP ; inositol phosphate ; DAG ; diacylglycerol ; PKC ; protein kinase C ; MAPK ; mitogen-activated protein kinase ; PKA ; protein kinase A ; U73122 ; 1-[6-((17尾-3-Methoxyestra-1 ; 3 ; 5(10)-trien-17-yl)ami
• 刊名：Molecular and Cellular Endocrinology
• 出版年：15 February, 2014
• 年：2014
• 卷：382
• 期：2
• 页码：851-859
• 全文大小：2103 K

文摘

Somatostatin is the most effective inhibitor of GH release, and GHRH was recently identified as one of the primary GH-releasing factors in teleosts. In this study, we analyzed the possible intracellular transduction pathways that are involved in the mechanisms induced by SRIF and GHRH to regulate GH release. Using a pharmacological approach, the blockade of the PLC/IP/PKC pathway reversed the SRIF-induced inhibition of GH release but did not affect the GHRH-induced stimulation of GH release. Furthermore, SRIF reduced the GH release induced by two PKC activators. Inhibitors of the AC/cAMP/PKA pathway reversed both the SRIF- and GHRH-induced effects on GH release. Moreover, the GH release evoked by forskolin and 8-Br-cAMP were completely abolished by SRIF. The blockade of the NOS/NO pathway attenuated the GHRH-induced GH release but had minimal effects on the inhibitory actions of SRIF. In addition, inhibitors of the sGC/cGMP pathway did not modify the SRIF- or GHRH-induced regulation of GH release. Taken together, these findings indicate that the SRIF-induced inhibition of GH release is mediated by both the PLC/IP/PKC and the AC/cAMP/PKA pathways and not by the NOS/NO/sGC/cGMP pathway. In contrast, the GHRH-induced stimulation of GH secretion is mediated by both the AC/cAMP/PKA and the NOS/NO pathways and is independent of the sGC/cGMP pathway and the PLC/IP/PKC system.