title: 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).
abstract: 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.
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Chaobin
authors.initials: C
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Jirong
authors.initials: J
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address: lsslws@mail.sysu.edu.cn.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Li
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000235:genetics* / Q000378:metabolism; D013007:Growth Hormone-Releasing Hormone / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010473:Perciformes; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D061251:Primary Cell Culture; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D017481:Receptors, Somatostatin / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013004:Somatostatin / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D017481:Receptors, Somatostatin; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D009569:Nitric Oxide; D013004:Somatostatin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D011493:Protein Kinase C; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases; D006162:Guanylate Cyclase; D006152:Cyclic GMP
keywords: 1,2-dioctanoyl-sn-glycerol; 1-[6-((17β-3-Methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione; 2-[1-(3-Dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3-yl)-maleimide; 6-fenilanilino-5,8-quinolinedione; AC; BSA; DA; DAG; DiC8; FBS; G-protein-coupled receptor; GF109203X; GH; GH release; GH-releasing hormone; GHRH; GHRH receptor; GHRH-R; GPCR; GnRH; H89; IP; L-AME; L-NAME; L-arginine methyl ester dihydrochloride; LY-83583; MAPK; MDL-12,330A; N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide; NO; NOS; Nw-nitro-L-arginine methyl ester hydrochloride; PACAP; PBS; PKA; PKC; PLC; Primary pituitary cell cultures; S-nitroso-N-acetylpenicillamine; SNAP; SRIF; SSTR; Signaling pathway; Somatostatin; TPA; U73122; adenosine 3′,5′-cyclic monophosphate; adenylate cyclase; bovine serum albumin; cAMP; cGMP; cis-N-(2-Phenylcyclopentyl)azacyclotridec-1-en-2-amine; diacylglycerol; dopamine; fetal bovine serum; gonadotropin-releasing hormone; growth hormone; guanosine 3′,5′-cyclic monophosphate; inositol phosphate; mitogen-activated protein kinase; nitric oxide; nitric oxide synthase; phorbol 12-myristate-13-acetate; phosphate buffered saline; phospholipase C; pituitary adenylate cyclase-activating peptide; protein kinase A; protein kinase C; sGC; soluble guanylate cyclase; somatostatin receptor; somatotropin release-inhibitory factor