Regulation of solute and water balance in primitive fishes

内分泌控制溶质和水分平衡是所有生物体的生命维持过程。它需要许多不同的生理系统通过多种激素的相互作用来协调行动。血管紧张素II、C型利钠肽、缓激肽和精氨酸血管生成素等激素均参与哺乳动物体内的溶质和水分调节。研究表明，这些荷尔蒙也存在于从系统发育上来说古老的弹齿目鱼类中，并具有生理功能。拟议的研究计划将研究这些激素在调节弹棘鱼的肾脏、心血管和胃肠生理方面所起的作用。此外，尿素和氨的关键转运蛋白的分子特征将提供有关弹性支链动物氮素平衡的新信息。此外，还将研究解脲细菌在这些原始鱼类的氮代谢中可能起到的作用。这项拟议的研究具有重要意义，因为它旨在为脊椎动物中的溶质运输机制提供一个进化框架，并从生理上理解激素系统如何调节棘足目鱼类类似的生理功能。另一项研究是关于第二种原始鱼类--湖泊鲟鱼的钙转运和这一关键离子的内分泌调节。这些淡水软骨鱼在钙调节方面呈现出一种独特的模式。除了激素调节外，对这种离子的转运机制的分子表征将有助于我们了解这些鱼类的钙代谢，因此拟议的研究将有助于缓解环境钙下降对这种受威胁物种的潜在影响。因此，从这一拟议研究方案中获得的信息不仅可以用于工业，因为这项基础性研究是在制药业开发治疗学方面更先进和更具创新性的研究的基础，也可以从保护诸如湖泊鲟鱼等受威胁物种的保护生理学的背景下使用。

Endocrine control of solute and water balance is a life sustaining process in all organisms. It requires the coordinated action of a number of different physiological systems through the interaction of a multitude of hormones. Hormones such as angiotensin II, C-type natriuretic peptide, bradykinin and arginine vasotocin are all involved in solute and water regulation in mammals. Research has shown that these hormones also exist, and have physiological function, in the phylogenetically ancient elasmobranch fish. The proposed research programme will examine the role these hormones play in the regulation of renal, cardiovascular and gastro-intestinal physiology of elasmobranch fish. In addition, molecular characterisation of key transport proteins for urea and ammonia will provide new information on nitrogen balance in elasmobranchs. Furthermore, the role ureolytic bacteria may play in nitrogen metabolism in these primitive fish will be examined. The proposed research is significant as it aims to provide an evolutionary framework for solute transport mechanisms in vertebrates and a physiological understanding of how hormone systems regulate similar physiological functions in elasmobranch fish. Additional research is proposed to examine calcium transport and the endocrine regulation of this key ion in a second primitive fish, the lake sturgeon. These freshwater cartilaginous fish present a unique model in terms of calcium regulation. Molecular characterisation of transport mechanisms in addition to hormonal regulation of this ion will aid in our understanding of calcium metabolism in these fish and therefore the proposed research will aid in the mitigation of potential impacts in the documented declines of environmental calcium may have on this threatened species. Therefore, information gained from this proposed research programme can be used not only in the context of industry as this fundamental research underpins more advanced and innovative research in the development of therapeutics in the pharmaceutical industry but also from the context of conservation physiology for the protection of threatened species such as the lake sturgeon.