RUI: Effects of Dehydration During Growth on Avian Kidney Development

脱水是许多生物在其一生中可能遇到的压力源，包括身体生长和器官发育时期。脱水会引起激素水平的变化，包括抗利尿激素水平的显著增加，而受限制的水分会抑制全身的生长。总之，这些因素可能影响许多器官系统的生长和发育。这项研究将特别关注生长过程中脱水对肾脏发育的影响，肾脏是抗利尿激素的主要靶器官。PI将在山鹑中研究这个问题，山鹑是一种雏鸟在孵化后不久就必须自己觅食的物种，因此在生命的早期阶段非常有可能脱水。初步数据表明，当鸟类长期饮水受限时，肾脏（肾髓质）区域主要与脱水过度期间的水分保存有关。与此相关的是尿液浓缩能力的增强，这应该有助于加强节水。本研究将进一步探讨慢性脱水对功能的影响，特别是研究集中能力增强的基础。这是否反映了尿形成速率的变化，激素水平的变化，或细胞对激素反应的变化？脱水引起的形态学改变如何与功能变化相关？这些变化是可逆的，还是在青年时期施加的压力会持续到成年？这些研究将有助于确定动物对脱水的生理反应。他们还将研究鸟类肾脏的结构和功能之间的关系，这方面还有很多未知或推测。更一般地说，这些研究将检查一个重要的体内平衡系统的灵活性，并将解决环境压力对发育途径的重要性的一般问题。这种方法应该确定禽肾在设计和功能上的限制。这既与个体适应不断变化的环境的能力有关，也与物种入侵和适应不同栖息地的能力有关。

Dehydration is a stressor that may be encountered by many organisms during their lifetimes, including the period of body growth and organ development. Dehydration induces changes in hormone levels, including prominently increases in levels of anti-diuretic hormone, and the restricted water inhibits general body growth. Together, these factors may influence the growth and the development of many organ systems. The research will focus particularly on the effects of dehydration during growth on development of the kidney, a principle target organ for anti-diuretic hormone. The PI will study this problem in bobwhite quail, a species in which the chicks must forage for themselves beginning shortly after hatching, and in which therefore there is a very real possibility of dehydration during the early life stages. Preliminary data suggest that the region of the kidney (the renal medulla) primarily concerned with water conservation during dehydration hypertrophies when the birds are chronically water restricted. Associated with this is an enhanced ability to concentrate the urine, which should contribute to enhanced water conservation. The proposed research will further explore the functional consequences of chronic dehydration, and in particular will examine the basis for the enhanced concentrating ability. Does this reflect changes in the rate of urine formation, changes in hormone levels, or changes in the cellular response to the hormone? How do morphological changes induced by dehydration correlate with changes in function? Are these changes reversible, or do stresses imposed during youth have consequences that continue into adulthood? These studies will help to define the physiological responses of animals to dehydration. They will also examine the relation between structure and function in the avian kidney, about which much remains unknown or speculative. More generally, these studies will examine the flexibility of an important homeostatic system, and will address the general issue of the importance of environmental stresses on developmental pathways. This approach should identify constraints in design and function of the avian kidney. This relates both to the ability of individuals to acclimate to changing environments, as well as to the ability of species to invade and adapt to different habitats.