作　　者： ; ; (冉雪琴）;

机构地区： 中山大学生命科学学院水生经济动物研究所

出　　处： 《动物学报》 2004年第2期222-230,共9页

摘　　要： 斜带石斑鱼 (Epinepheluscoioides)属于雌性先成熟、具有性转变的雌雄同体鱼类。生长激素释放抑制因子 (SRIF)是鱼类生长激素 (GH)分泌的主要抑制性调节剂 ,半胱胺 (CSH)可抑制SRIF的作用。本文采用静态孵育系统 ,应用RPA及RIA研究SRIF及CSH对斜带石斑鱼GHmRNA表达及GH分泌的调节。结果显示 ,SRIF能以剂量依存方式抑制斜带石斑鱼脑垂体释放GH ,时间越长作用越强。但SRIF作用 2 4h对GHmR NA水平的影响不显著 ,表明SRIF是斜带石斑鱼GH释放的抑制性调节剂 ,对GHmRNA的表达没有明显影响。较低剂量的CSH (10 -4- 10 -2 mol/L)使斜带石斑鱼的GH释放量增加 ,较高剂量 (10 -1mol/L)的CSH引起的GH增加趋势减缓 ,这种现象可能与较高剂量的CSH不仅抑制下丘脑SRIF的释放 ,同时影响GHRH的释放 ,使得GH的分泌量增幅下降有关 ;无论是较高剂量还是较低剂量的CSH都不能使GHmRNA的水平增加 ,表明CSH只能引起GH的释放量增加 ,不影响GH的合成。GnRH与CSH共同作用引起的GH释放量明显高于CSH单独作用的效应 。 The regulation of growth hormone(GH)synthesis and secretion in teleosts is based on the dual control of hypothalamic stimulators,the gonadotropin-releasing hormone(GnRH),dopamine(DA),growth hormone-releasing hormone(GHRH),and the inhibitors,somatostatin(SRIF),norepinephrine(NE).SRIF is the main inhibitor of basal and neuroendocrine-stimulated GH release.Cysteamine(CSH)is a potent somatostatin depletor and promotes the growth of animal and grass carp obviously.Orange-spotted grouper Epinephelus coioides is known as a benthic protogynous marine fish with sex inversion.The effects of SRIF and CSH on the GH release and GH mRNA expression in orange-spotted grouper still remain unclear.We studied whether SRIF and CSH modulate the release of GH and regulate the expression of GH mRNA in the pituitary of orange-spotted grouper.SRIF or CSH was incubated with the pituitary fragments of the orange-spotted grouper in static culture system.The GH content in the incubation medium was detected by homologous radioimmunoassay(RIA),and the GH mRNA level in the pituitary fragments was measured with RNase protection assay(RPA)taken digoxigenin-labelled antisense RNA as probe.The RPA could detect as little as 1 pg sense RNA or GH mRNA in 0.5 μg total RNA of pituitary.SRIF(10 -8-10 -6 mol/L)significantly inhibited the GH release at 2 h by 64.28%-13.72% compared to the control group,and the inhibited effects was much more obvious at 24 h by only 3.3%-2.36% of the control.CSH at doses of 10 -4,10 -3 and 10 -2 mol/L significantly increased the GH release at 2 h by 64.28%-13.72% of the control.The CSH effect of 10 -1 mol/L was smaller than that of 10 -2 mol/L.The trend of higher dose of CSH with smaller effects was very apparent when the incubation duration was prolonged to 24 h.10 -4,10 -3 and 10 -2 mol/L CSH increased GH release by 162.4%-467% of control.GH content exposed to 10 -1 mol/L CSH was just 184.83% of control,which was comparable with that to 10 -4 mol/L CSH.It might be related to the reduction of GHRH from hypotha

关 键 词： 斜带石斑鱼 生长激素 生长激素释放抑制因子 半胱胺

领　　域： [生物学]