Perelló-Amorós Miquel, Vélez Emilio J, Vela-Albesa Jaume, Sánchez-Moya Albert, Riera-Heredia Natàlia, Hedén Ida, Fernández-Borràs Jaume, Blasco Josefina, Calduch-Giner Josep A, Navarro Isabel, Capilla Encarnación, Jönsson Elisabeth, Pérez-Sánchez Jaume, Gutiérrez Joaquim
Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
Fish Endocrinology Laboratory, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
Front Endocrinol (Lausanne). 2018 Jul 30;9:399. doi: 10.3389/fendo.2018.00399. eCollection 2018.
Ghrelin is involved in the regulation of growth in vertebrates through controlling different functions, such as feed intake, metabolism, intestinal activity or growth hormone (Gh) secretion. The aim of this work was to identify the sequences of and Ghrelin receptors (), and to study their responses to different nutritional conditions in gilthead sea bream () juveniles. The structure and phylogeny of was analyzed, and a tissue screening was performed. The effects of 21 days of fasting and 2, 5, 24 h, and 7 days of refeeding on plasma levels of Ghrelin, Gh and Igf-1, and the gene expression of and members of the Gh/Igf-1 system were determined in key tissues. and the receptors are well conserved, being expressed mainly in stomach, and in the pituitary and brain, respectively. Twenty-one days of fasting resulted in a decrease in growth while Ghrelin plasma levels were elevated to decrease at 5 h post-prandial when pituitary expression was minimum. Gh in plasma increased during fasting and slowly felt upon refeeding, while plasma Igf-1 showed an inverse profile. Pituitary expression augmented during fasting reaching maximum levels at 1 day post-feeding while liver expression and that of its splice variants decreased to lowest levels. Liver Gh receptors expression was down-regulated during fasting and recovered after refeeding. This study demonstrates the important role of Ghrelin during fasting, its acute down-regulation in the post-prandial stage and its interaction with pituitary Ghsrs and Gh/Igf-1 axis.
胃饥饿素通过控制不同功能参与脊椎动物的生长调节，如摄食、新陈代谢、肠道活动或生长激素（Gh）分泌。本研究的目的是鉴定金头鲷幼鱼胃饥饿素及其受体（Ghsrs）的序列，并研究它们对不同营养条件的反应。分析了Ghsrs的结构和系统发育，并进行了组织筛选。测定了21天禁食以及再投喂2、5、24小时和7天对金头鲷幼鱼关键组织中胃饥饿素、Gh和Igf-1血浆水平以及Ghsrs和Gh/Igf-1系统成员基因表达的影响。Ghsrs及其受体高度保守，分别主要在胃、垂体和脑中表达。21天禁食导致生长下降，而胃饥饿素血浆水平升高，在餐后5小时垂体Ghsrs表达最低时下降。禁食期间血浆Gh增加，再投喂后缓慢下降，而血浆Igf-1呈现相反的变化趋势。垂体Ghsrs表达在禁食期间增加，在投喂后1天达到最高水平，而肝脏Ghsrs表达及其剪接变体的表达下降到最低水平。肝脏Gh受体表达在禁食期间下调，再投喂后恢复。本研究证明了胃饥饿素在禁食期间的重要作用、其在餐后阶段的急性下调以及它与垂体Ghsrs和Gh/Igf-1轴的相互作用。
