State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China.
Mol Cell Endocrinol. 2013 Aug 25;376(1-2):114-24. doi: 10.1016/j.mce.2013.06.020. Epub 2013 Jun 24.
As in mammals, fatty acid (FA) metabolism plays diverse and vital roles in regulating food intake in fish. Multiple lines of evidence suggest that the effect of FA metabolism on food intake is linked to changes in the level of neuropeptide Y (NPY) in the hypothalamus of the rainbow trout. In mammals, the evidence suggests that FA metabolism regulates feeding via hypothalamic NPY. NPY is therefore considered an important factor that mediates the modulation of food intake by FA metabolism in vertebrates. The stimulatory effect of NPY on food intake is well known. However, to the best of our knowledge, the effect of NPY on FA metabolism in the hypothalamus has not been examined. In this study, we cloned the cDNA of four key enzymes involved in FA metabolism and assessed the effect of energy status and NPY on their mRNA expression in the hypothalamus of grouper. The full-length cDNAs of UCP2 and CPT1a and the partial coding sequence (CDS) of ACC1 and FAS were isolated from the grouper hypothalamus. These genes are expressed in the hypothalamus and during the organogenetic stage of embryogenesis. A feeding rhythm study showed that the hypothalamic expression level of NPY and CPT1a was highly correlated with feeding rhythm. Long-term fasting was found to significantly induce the hypothalamic mRNA expression of NPY, CPT1a and UCP2. An in vitro study demonstrated that NPY strongly stimulated CPT1a and UCP2 mRNA expression in a time- and dose-dependent manner. Collectively, these results suggest that these four genes related to FA metabolism may play a role in regulating food intake in grouper and, that NPY modulates FA metabolism in the grouper hypothalamus. This study showed, for the first time in vertebrates, the effect of NPY on the gene expression of FA metabolism-related enzymes.
在哺乳动物中，脂肪酸（FA）代谢在调节鱼类摄食方面发挥着多样化的重要作用。有多项证据表明，FA 代谢对摄食的影响与虹鳟鱼下丘脑神经肽 Y（NPY）水平的变化有关。在哺乳动物中，有证据表明 FA 代谢通过下丘脑 NPY 调节摄食。因此，NPY 被认为是介导脊椎动物 FA 代谢调节摄食的重要因素。NPY 对摄食的刺激作用是众所周知的。然而，据我们所知，NPY 对 FA 代谢在下丘脑的影响尚未得到检验。在本研究中，我们克隆了参与 FA 代谢的四个关键酶的 cDNA，并评估了能量状态和 NPY 对其在石斑鱼下丘脑 mRNA 表达的影响。从石斑鱼下丘脑分离出 UCP2 和 CPT1a 的全长 cDNA 以及 ACC1 和 FAS 的部分编码序列（CDS）。这些基因在脑下垂体中表达，并在胚胎发生的器官发生阶段表达。摄食节律研究表明，NPY 和 CPT1a 的下丘脑表达水平与摄食节律高度相关。长期禁食显著诱导 NPY、CPT1a 和 UCP2 的下丘脑 mRNA 表达。体外研究表明，NPY 以时间和剂量依赖的方式强烈刺激 CPT1a 和 UCP2 mRNA 的表达。综上所述，这些与 FA 代谢相关的四个基因可能在调节石斑鱼摄食中发挥作用，并且 NPY 调节石斑鱼下丘脑的 FA 代谢。本研究首次在脊椎动物中显示了 NPY 对 FA 代谢相关酶基因表达的影响。
