Search for the genes responsible for adaptation to marine environments: osmoregulatory hormone genes

海洋是生命的发源地，一般来说是生物体生存的舒适环境。然而，海水的高渗透压对血浆渗透压只有海水三分之一的海洋硬骨鱼构成了沉重的负担。在这种高渗环境中，激素在体液调节中起核心作用。然而，在海水适应中发挥关键作用的主要激素迄今尚未确定，尽管加压素/催产素被确定为适应陆地环境的必要激素。因此，我们在河豚和青鳉的基因组数据库中寻找钠挤压激素，它们在硬骨鱼中的多样性更高。例如，在硬骨鱼类中，有7种利钠肽（NPs）的旁系同源物，在哺乳动物中远远多于3种，并且其中一种NPs，心房NP（ANP），被发现是硬骨鱼类中的主要海水适应激素。心钠素通过抑制海水鳗鱼饮水和随后的钠吸收降低血浆钠浓度 ...更多信息 Cl通过肠道，从而促进海水适应。肾上腺髓质素在哺乳动物中是一种水和钠的分泌激素，但在硬骨鱼中形成了一个独立的5个旁系同源物（AM 1，2，3，4和5）的亚家族。此外，我们在哺乳动物中发现了AM 2和AM 5。AM 2具有抑制哺乳动物饮水、催产素分泌等体液调节中枢作用，AM 5可能与免疫系统调节有关。AM 2和AM 5具有强的致渴和抗利尿作用，因此这些激素可能促进硬骨鱼的海水适应。鸟苷素是一种肠道激素，通过将Cl离子分泌到肠腔中引起哺乳动物腹泻，水与肠腔平行移动。在硬骨鱼中，鸟苷素也刺激肠中的Cl分泌。然而，分泌的Cl离子通过Na-K-2Cl共转运蛋白与Na和K一起吸收，另外两种渗透剂从管腔移动到体内，导致水的吸收。因此，鸟苷素可能通过获得更多的水来科普脱水，从而促进海水适应。总之，我们可以通过JSPS支持的三年项目确定促进海水适应的主要激素。少

The sea, from which the life originates, is generally a comfortable environment for living organism. However, high osmotic pressure of seawater poses a heavy burden to marine teleosts that have plasma osmotic pressure only one third of seawater. Hormones play central roles in body fluid regulation in such hyperosmotic environmental. However, major hormones that play key roles in seawater adaptation have not been identified thus far, although vasopressin/vasotocin is identified as an essential hormone to adapt to the terrestrial environment. Therefore, we search for Na-extruding hormones in the genome database of pufferfish and medaka, and they are much diversified in teleost fish. For instance, natriuretic peptides (NPs) have 7 paralogs in teleost, much more than 3 in mammals, and one of the NPs, atrial NP (ANP), is found to be a major seawater-adapting hormone in teleost fish. ANP decreases plasma Na concentration in seawater eels by inhibiting drinking and subsequent absorption of Na … More Cl by the intestine, thereby promoting seawater adaptation. Adrenomedullin is a water and Na-extruding hormone in mammals, but it forms an independent subfamily of 5 paralogs (AM1, 2, 3, 4 and 5) in teleost fish. Further, we discovered AM2 and AM5 in mammals. AM2 has potent central actions for body fluid regulation such as inhibition of drinking and oxytocin secretion in mammals, while AM5 may be related to regulation of immune system. AM2 and AM5 have a potent dipsogenic and antidiuretic effects, so that these hormones may promoter seawater adaptation in teleost fish. Guanylin, an intestinal hormone, causes diarrhea in mammals by secreting Cl ions into the lumen of the intestine, with which water moves in parallel. In teleost fish, guanylin also stimulates Cl secretion in the intestine. However, the secreted Cl ions are absorbed with Na and K through Na-K-2Cl co-transporter, two more osmolytes moves from the lumen into the body, resulting in absorption of water. Therefore, guanylin may promote seawater adaptation by acquiring more water to cope with dehydration. In summary, we could identify major hormones that promote seawater adaptation through the three-year project supported by JSPS. Less