The nonapeptide hormone arginine vasotocin (VT) regulates osmotic balance in fishes by modulating ion and water transport. While VT’s osmoregulatory effects arise in part via changes in VT secretion, it remains uncertain which nonapeptide receptors mediate these effects, or whether adjustments in VT degradation also contribute. This study characterized gene transcript profiles for all known teleost nonapeptide receptors and for the VT and isotocin (IT) degradation enzyme leucyl-cystinyl aminopeptidase (lnpep) in the gill, kidney, and intestine – as well as transcriptional profiles for proVT and proIT mRNAs in hypothalamus and pituitary – of blue tilapia (Oreochromis aureus) during hyperosmotic challenge. Results presented here suggest that VT’s actions during salinity acclimation may be mediated by V1a-type receptor V1a2 in gill and intestine but multiple V2-type receptors in kidney, and provide evidence that lnpep expression is modulated concurrent with osmoregulation, possibly to alter local availability of nonapeptides as osmolality returns to homeostatic set points.

九肽激素精氨酸血管收缩素（VT）通过调节离子和水的运输来调节鱼类的渗透平衡。虽然VT的渗透调节作用部分是由VT分泌的变化引起的，但仍不确定哪些非肽受体介导这些作用，或者尚不清楚VT降解的调节是否也起作用。这项研究表征了所有已知的硬骨非肽受体以及gene，肾和肠中VT和同位素降解酶亮氨酰半胱氨酰氨基肽酶（Inpep）的基因转录谱， 以及其中的proVT和 proIT  mRNA的转录谱 。下丘脑和垂体–蓝色罗非鱼（Oreochromis aureus）。此处显示的结果表明，盐度适应过程中VT的作用可能由g和肠中的V1a型受体V1a2介导，但肾脏中有多个V2型受体介导，并提供了lnpep 表达与渗透调节同时被调节的证据 ，可能改变了局部的可用性。重量摩尔渗透压浓度恢复到稳态设定点。