Efficiency of utilization of urea nitrogen for albumin synthesis by chronically uraemic and normal man.
Efficiency of utilization of urea nitrogen for albumin synthesis by chronically uraemic and normal man.
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慢性尿毒症和正常人利用尿素氮合成白蛋白的效率。
DOI：
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发表时间：
1975
期刊：
影响因子：
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通讯作者：
A. Tavill
中科院分区：
文献类型：
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作者：
R. Varcoe;D. Halliday;E. Carson;P. Richards;A. Tavill
1.本文研究了10例慢性肾功能衰竭患者和4例正常人单次静脉注射[~（14）C]尿素、[~（15）N]尿素和~（125）I标记白蛋白后内源性尿素代谢与白蛋白合成的关系。2.根据血浆[14-C]尿素比放射性的动态测定尿素合成速率，并根据尿素合成的相对速率和尿液和体液中尿素的出现率估计尿素代谢速率。血浆[15 N]白蛋白富集和125-i标记白蛋白放射性的去卷积分析产生了15-N累积掺入总可交换白蛋白中，并能够计算白蛋白合成的尿毒症氮利用的绝对速率。3.虽然尿毒症患者尿素降解的平均绝对速率（3-7 mmol/h）高于正常人（2-3 mmol/h），但尿素降解与血浆尿素浓度之间无显著正相关。4.尿毒症患者尿素合成率与尿素降解率呈显著正相关。5.尿素氮用于白蛋白合成的速率较低，但尿毒症患者（平均83-8 mumol/h）的利用率远远高于正常患者（平均6-4 mumol/h），尿毒症患者（2-37%）白蛋白合成所需的尿素氮供应率也高于正常患者（0-13%）。6.尿毒症患者利用尿素氮合成白蛋白的效率（1-3%）高于正常人（0-2%），慢性肾功能衰竭患者中接受30 g蛋白质饮食的患者高于接受70 g蛋白质饮食的患者。尿素氮利用率与白蛋白合成率呈显著负相关。7.这些研究表明，慢性肾衰竭中存在一种与尿素降解程度无关的尿素氮保存机制，这只能部分解释为来自尿素的管腔内肠氮比例较高。
1. The relation between endogenous urea metabolism and albumin synthesis has been studied in ten patients with chronic renal failure and in four normal subjects, after single intravenous injections of [14-C]urea,[15-N]urea and 125-I-labelled albumin. 2. The rate of urea synthesis was determined from the dynamics of plasma [14-C]urea specific radioactivity and the rate of urea metabolism was estimated from the relative rates of urea synthesis and urea appearance in urine and body water. Deconvolution analysis of plasma [15N]albumin enrichmevt and 125-i-labelled albumin radioactivity yielded the cumulative incorporation of 15-N into total exchangeable albumin and enabled calculation of the absolute rate of urema nitrogen utilization for albumin synthesis. 3. Although the mean absolute rate of urea degradation in uraemic patients (3-7 mmol/h) was higher than in normal subjects (2-3 mmol/h) there was no significant positive correlation between urea degradation and plasma urea concentration. 4. In uraemic subjects, there was a significant positive correlation between urea synthetic rate and urea degration rate. 5. The rate of utilization of urea nitrogen for albumin synthesis was low, but was very much higher in uraemic subjects (mean 83-8 mumol/h) compared with normal subjects (mean 6-4 mumol/h), as was the provision by urea of the nitrogen required for albumin synthesis in uraemic subjects (2-37%) compared with normal subjects (0-13%). 6. The efficiency of utilization of urea nitrogen for albumin synthesis was higher in the uraemic patients (1-3%) than the normal subjects (0-2%), and was higher in those patients with chronic renal failure who received a 30 g protein diet than those on 70 g of protein. A significant negative correlation was noted between efficiency of urea nitrogen utilization and the rate of synthesis of albumin. 7. These studies suggest the presence of a mechanism for the conservation of urea nitrogen in chronic renal failure which is unrelated to the extent of urea degradation, and which can only be partly explained by the higher proportion of intraluminal gut nitrogen derived from urea.