Zebrafish ghrelin is expressed in pancreatic endocrine cells and regulated by metabolic state
Zebrafish ghrelin is expressed in pancreatic endocrine cells and regulated by metabolic state
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DOI：
10.1016/j.bbrc.2013.08.017
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发表时间：
2013-09-13
影响因子：
3.1
通讯作者：
Song, Youngsup
中科院分区：
文献类型：
--
作者：
Eom, Ji;Hong, Minsun;Song, Youngsup
哺乳动物生长激素释放肽是一种胃源性肽，可刺激生长激素分泌和食物摄入。斑马鱼是一个很好的模型系统，为向前遗传研究，许多方面的能量稳态特征的哺乳动物似乎是保守的斑马鱼。在本研究中，我们研究了斑马鱼ghrelin的表达和调节代谢状态。定量RT-PCR结果显示，斑马鱼ghrelin在前肠相关组织中高度富集。使用原位杂交与成年斑马鱼组织，我们发现，斑马鱼ghrelin mRNA不表达在肠组织，而是在集群的内分泌胰腺细胞不同的胰岛素表达胰岛。禁食特异性地上调胰腺生长素释放肽而不是脑生长素释放肽表达3至4倍，并且再喂食在5小时内将生长素释放肽转录物恢复到喂食组中观察到的对照水平。这些结果表明，尽管生长素释放肽在斑马鱼中的不同位点表达，但它以与哺乳动物生长素释放肽类似的方式响应代谢状态，表明在硬骨鱼中的摄食调节中的作用，从而验证了斑马鱼作为分析生长激素释放肽系统和能量稳态的遗传模型系统的实用性。(C)2013 Elsevier Inc. All rights reserved.
Mammalian ghrelin is a stomach-derived peptide that stimulates secretion of growth hormone and food intake. Zebrafish is an excellent model system for forward genetic studies, and many aspects of energy homeostasis characterized in mammals appear to be conserved in the zebrafish. In this study, we investigated the expression and regulation of zebrafish ghrelin by metabolic status. Quantitative RT-PCR revealed that zebrafish ghrelin is highly enriched in anterior gut associated tissues. Using in situ hybridization with adult zebrafish tissues, we found that zebrafish ghrelin mRNA was not expressed in intestine tissue, but rather in clusters of endocrine pancreas cells distinct from insulin-expressing islets. Fasting specifically upregulated pancreatic ghrelin but not brain ghrelin expression by 3- to 4-fold and refeeding restored ghrelin transcript to control levels seen in the fed group within 5 h.These results demonstrate that although ghrelin is expressed in a different site in zebrafish, it is responsive to metabolic state in a similar manner as mammalian ghrelin, suggesting a role in the regulation of feeding in teleosts, and thus validate the utility of zebrafish as a genetic model system for the analysis of the ghrelin system and energy homeostasis. (C) 2013 Elsevier Inc. All rights reserved.