Urea Transport in the Elasmobranch Kidney

人体肾脏的功能是清除体内的废物，同时也调节血液和体液中的盐和水的成分。尿素是蛋白质代谢的分解产物，通常被认为是肾脏排泄的废物。事实确实如此，但尿素在正常的肾脏功能中也起着重要作用。肾脏以一种复杂的方式使用尿素来增加尿液的浓度，这样在肾脏中形成的初始尿液中只有一小部分实际被排出。事实上，肾功能异常反映在尿素排泄量的变化上--这种情况被称为尿毒症。与尿素有关的细胞功能障碍的机制在人类和实验哺乳动物中都极难研究。莱西博士将研究鲨鱼和溜冰的肾脏，原因如下：1)令人惊讶的是，溜冰的肾脏在结构上与人类非常相似，这是莱西在1985年做出的发现。2)这些动物的血液和组织中的尿素浓度极高，但肾脏不会排泄很多。3)冰鞋比实验大鼠更适合作为PI的实验动物。莱西博士的研究旨在了解溜冰肾脏在正常生理状态下如何处理尿素。PI的数据将适用于人类肾脏功能和疾病。

The human kidney functions to rid the body of waste products, but also to regulate the salt and water composition of the blood and body fluids. Urea is a breakdown product of protein metabolism and generally perceived to be a waste product excreted by the kidney. This is indeed the case, but urea also plays an important role in normal kidney function. Urea is used in a complex manner by the kidney to augment concentration of the urine, such that only a small fraction of the initial urine formed in the kidney is actually excreted. Indeed, abnormal kidney function is reflected in changes in the amount of urea that is excreted - a condition called uremia. The mechanisms of cellular dysfunction in regards to urea are extremely difficult to study in human as well as laboratory mammals. Dr. Lacy will study shark and skate (elasmobranchs) kidney because of the following reasons: 1) Surprisingly, the skate kidney is remarkably similar in structure to that of humans, a finding Dr. Lacy made in 1985. 2) These animals have extremely high concentrations of urea in their blood and tissues, but the kidney does not excrete very much of it. 3) Skates are a more suitable alternative than laboratory rats for the PI's experimental animal. Dr. Lacy's research is directed to understanding how the skate kidney handles urea in its normal physiology. The PI's data will be applicable to human kidney function and disease.