Spexin (Spx), an endogenous peptide, is considered to be a neuropeptide. In a few fish and mammals, it has been proved to play a role in the regulation of animal feeding. However, the possible mechanisms of spexin regulating food intake are mostly blurry in vertebrates including Siberian sturgeon. In this study, firstly, the coding sequence of spexin cDNA was cloned and sequenced in Siberian sturgeon. Then, we detected that spexin mRNA was widely expressed in the hypothalamus, gastrointestinal tract, and liver, with the highest expression in the hypothalamus. The expression of spexin mRNA in the hypothalamus was significantly increased after food intake. At 1 h, 3 h, and 6 h after injection, the food intake in the spexin group (0.10, 0.30, and 0.90 μg/g BW) was significantly lower than that in the saline group. Moreover, compared with the saline group, the mRNA expression of anorectic nucb2, cart, ucn3, and pyy in the hypothalamus was significantly upregulated and orectic npy was significantly downregulated at 1 h after spexin injection; in the stomach, the mRNA expression of nucb2 and pyy was significantly upregulated. All in all, these results provide evidence for the anorexic effect of spexin on Siberian sturgeon.

内源肽Spexin（Spx）被认为是神经肽。在一些鱼类和哺乳动物中，已证明它在调节动物摄食中起作用。但是，在包括西伯利亚st鱼在内的脊椎动物中，spexin调节食物摄入的可能机制大多模糊。在这项研究中，首先，在西伯利亚st中克隆了spexin cDNA的编码序列。然后，我们检测到spexin mRNA在下丘脑，胃肠道和肝脏中广泛表达，在下丘脑中表达最高。spexin的表达进食后下丘脑中的mRNA显着增加。注射后1h，3h和6h，spexin组的食物摄入量（0.10、0.30和0.90μg/ g BW）显着低于生理盐水组。此外，与生理盐水组相比，厌食的mRNA表达NUCB2，购物车，ucn3和PYY于下丘脑中显著上调和orectic NPY在spexin注射后1个小时被显著下调; 在胃中，nucb2和pyy的mRNA表达明显上调。总而言之，这些结果为斯皮辛对西伯利亚st的厌食作用提供了证据。