Balment R J, Song W, Ashton N
Faculty of Life Sciences, University of Manchester, UK.
Ann N Y Acad Sci. 2005 Apr;1040:66-73. doi: 10.1196/annals.1327.007.
Urotensin II (UII), described in many fish species, is secreted by the caudal neurosecretory system, a unique fish neuroendocrine structure. We have examined UII secretion and its control in euryhaline fish, supporting a proposed role in osmoregulation. However, it is now apparent that UII is present in other vertebrates, including mammals. The 12-amino-acid peptide has been highly conserved and the key cyclic region is common from fish to humans. Our UII radioimmunoassay for flounder, directed to this cyclic region, has shown circulating UII levels in humans and rats comparable with those in fish. In mammals, UII cardiovascular effects vary between species, with vasoconstriction only evident in specific vascular beds. The kidney expresses UII receptors and responds to UII administration by a reduction in glomerular filtration rate, urine flow, and excretion of the major ions. Interestingly, plasma levels of UII are chronically elevated in rat models of hypertension. These observations imply an unforeseen role for this ancient fish hormone in the physiological and perhaps pathophysiological regulation of body fluids in higher vertebrates, including humans.
尾加压素II（UII）在许多鱼类中都有描述，它由尾部神经分泌系统分泌，这是一种独特的鱼类神经内分泌结构。我们已经研究了广盐性鱼类中UII的分泌及其调控，这支持了其在渗透压调节中所起的作用。然而，现在很明显UII也存在于包括哺乳动物在内的其他脊椎动物中。这种由12个氨基酸组成的肽高度保守，其关键的环状区域从鱼类到人类都是相同的。我们针对比目鱼中这个环状区域的UII放射免疫分析表明，人类和大鼠体内循环的UII水平与鱼类相当。在哺乳动物中，UII对心血管的影响因物种而异，只有在特定血管床中才会出现血管收缩。肾脏表达UII受体，并通过降低肾小球滤过率、尿流量和主要离子排泄来响应UII的给药。有趣的是，在高血压大鼠模型中，UII的血浆水平长期升高。这些观察结果表明，这种古老的鱼类激素在包括人类在内的高等脊椎动物的生理甚至病理生理体液调节中发挥着意想不到的作用。
