Amiya Noriko, Mizusawa Kanta, Kobayashi Yuki, Yamanome Takeshi, Amano Masafumi, Takahashi Akiyoshi
School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
Zoolog Sci. 2012 Jan;29(1):43-8. doi: 10.2108/zsj.29.43.
Orexins (orexin-A and -B) are involved in the regulation of food intake in mammals. In the barfin flounder, Verasper moseri, we previously reported that orexin-A-like-immunoreactive (ir) cell bodies are localized in the hypothalamus, which is a possible orexigenic center in fish. However, the physiological roles of orexin in the barfin flounder remain unclear. Here, we cloned prepro-orexin cDNA and examined the effects of feeding status on orexin gene expression in the barfin flounder to obtain a better insight into the roles of orexins in feeding regulation. A molecular cloning study showed that barfin flounder prepro-orexin cDNA encodes a 145 amino acid (aa) polypeptide containing orexin-A (43 aa) and orexin-B (28 aa). Prepro-orexin gene transcripts were detected in the hypothalamus, pituitary, and several peripheral organs such as the eyeball, gills, head kidney, body kidney, spleen, testis, and the skin on the eye-side of the flounder's body. Furthermore, the mean prepro-orexin mRNA expression level in the hypothalamus was significantly higher in fasted than in fed fish. These results show that fasting regulates orexin mRNA in the hypothalamus and suggest that orexin is involved in feeding regulation in barfin flounder.
食欲素（食欲素-A和食欲素-B）参与哺乳动物的食物摄入调节。在条石鲷（Verasper moseri）中，我们之前报道过，食欲素-A样免疫反应性（ir）细胞体定位于下丘脑，下丘脑可能是鱼类的一个促食欲中心。然而，食欲素在条石鲷中的生理作用仍不清楚。在此，我们克隆了前食欲素cDNA，并研究了摄食状态对条石鲷食欲素基因表达的影响，以便更好地了解食欲素在摄食调节中的作用。一项分子克隆研究表明，条石鲷前食欲素cDNA编码一个由145个氨基酸（aa）组成的多肽，其中包含食欲素-A（43个aa）和食欲素-B（28个aa）。在前庭、垂体以及一些外周器官如眼球、鳃、头肾、体肾、脾脏、睾丸和条石鲷身体眼侧的皮肤中检测到了前食欲素基因转录本。此外，禁食条石鲷下丘脑前食欲素mRNA的平均表达水平显著高于喂食条石鲷。这些结果表明，禁食调节下丘脑食欲素mRNA水平，并提示食欲素参与条石鲷的摄食调节。
