Almdal T P, Jensen T, Vilstrup H
Division of Hepatology, Rigshospitalet, Copenhagen, Denmark.
Eur J Clin Invest. 1990 Feb;20(1):29-34. doi: 10.1111/j.1365-2362.1990.tb01787.x.
The relation of urea synthesis rate to blood alanine concentration was assessed in seven healthy controls and in 18 patients with insulin-dependent diabetes mellitus (HbAlc = 8.4 +/- 1.0% (mean +/- SD)). Following an overnight fast alanine was infused at 2 mmol h-1 kg-1 body weight. The hourly rate of urea synthesis was determined as the urinary excretion of urea corrected for accumulation of urea in total body water and intestinal hydrolysis. The functional hepatic nitrogen clearance, i.e. the relation of urea synthesis rate to blood alanine concentration, was calculated as the slope of linear regression of urea synthesis rates on blood alanine concentrations. Fasting glucagon concentrations were 85 +/- 26 ng l-1 in controls and 161 +/- 35 ng l-1 (P less than 0.01) in patients. The functional hepatic nitrogen clearances were 21.8 +/- 4.4 l h-1 in controls and 44.7 +/- 12.4 l h-1 (P less than 0.001) in patients. By multiple step-wise linear regression analysis the functional hepatic nitrogen clearance was found to correlate independently to fasting glucagon concentration, duration of diabetes, change in blood glucose and insulin following alanine infusion (r2 = 0.74). In a simple linear regression analysis the functional hepatic nitrogen clearance correlated strongly to fasting glucagon concentration (r2 = 0.54). In conclusion the kinetics of urea synthesis in insulin-dependent diabetes is changed in favour of increased conversion of alanine-N to urea-N at any blood amino acid concentration. The increased FHNC correlates strongly with hyperglucagonaemia.
在7名健康对照者和18名胰岛素依赖型糖尿病患者（糖化血红蛋白HbAlc = 8.4 +/- 1.0%（均值 +/- 标准差））中评估了尿素合成速率与血丙氨酸浓度的关系。在禁食过夜后，以2 mmol h-1 kg-1体重的速率输注丙氨酸。尿素合成的每小时速率通过校正全身水分中尿素积累和肠道水解后的尿素尿排泄量来确定。功能性肝氮清除率，即尿素合成速率与血丙氨酸浓度的关系，通过尿素合成速率对血丙氨酸浓度的线性回归斜率来计算。对照者的空腹胰高血糖素浓度为85 +/- 26 ng l-1，患者为161 +/- 35 ng l-1（P < 0.01）。对照者的功能性肝氮清除率为21.8 +/- 4.4 l h-1，患者为44.7 +/- 12.4 l h-1（P < 0.001）。通过多元逐步线性回归分析发现，功能性肝氮清除率与空腹胰高血糖素浓度、糖尿病病程、丙氨酸输注后血糖和胰岛素的变化独立相关（r2 = 0.74）。在简单线性回归分析中，功能性肝氮清除率与空腹胰高血糖素浓度密切相关（r2 = 0.54）。总之，在任何血氨基酸浓度下，胰岛素依赖型糖尿病患者的尿素合成动力学发生改变，有利于丙氨酸-N向尿素-N的转化增加。功能性肝氮清除率的增加与高胰高血糖素血症密切相关。
