Vilstrup H
Clin Physiol. 1984 Dec;4(6):495-507. doi: 10.1111/j.1475-097x.1984.tb00135.x.
The effect of glucose on alanine-stimulated urea synthesis was studied in six healthy volunteers during 6 h of constant alanine infusion, 2.8 mmol h-1 kg-1 b. wht., and during 12 h of constant glucose infusion, 4.0 mmol h-1 kg-1 b. wht., with superimposed alanine infusion. The urea nitrogen synthesis rate (UNSR) was determined at intervals of 2 h as urinary excretion rate corrected for accumulation and intestinal hydrolysis. UNSR depended on the blood alanine and glucagon concentration, but was not correlated with glucose, lactate, or insulin concentrations. The slope of the linear relation between UNSR and alanine concentration (the 'Functional Hepatic Nitrogen Clearance') was on the average 24.4 1 h-1 and decreased to 12.8 1 h-1 by glucose (mean difference +/- SE of the difference 10.6 +/- 7.3, P less than 0.01). The relation between glucagon and alanine concentration was linear, and the slope was decreased to 40 per cent by glucose (P less than 0.05). The slope of the linear relation between UNSR and glucagon was not changed by glucose. Thus the catabolism of alanine nitrogen is decreased by glucose because of a reduction of the urea synthesis. Data suggest that this may be due to a depression of the glucagon response to alanine.
在6名健康志愿者中，于持续输注丙氨酸（2.8 mmol·h⁻¹·kg⁻¹体重）6小时期间以及持续输注葡萄糖（4.0 mmol·h⁻¹·kg⁻¹体重）并叠加丙氨酸输注12小时期间，研究了葡萄糖对丙氨酸刺激的尿素合成的影响。每2小时测定一次尿素氮合成率（UNSR），以校正累积和肠道水解后的尿排泄率来确定。UNSR取决于血丙氨酸和胰高血糖素浓度，但与葡萄糖、乳酸或胰岛素浓度无关。UNSR与丙氨酸浓度之间线性关系的斜率（“功能性肝氮清除率”）平均为24.4 l·h⁻¹，葡萄糖使其降至12.8 l·h⁻¹（差值的平均差异±标准误为10.6±7.3，P<0.01）。胰高血糖素与丙氨酸浓度之间的关系是线性的，葡萄糖使其斜率降至40%（P<0.05）。葡萄糖未改变UNSR与胰高血糖素之间线性关系的斜率。因此，由于尿素合成减少，葡萄糖降低了丙氨酸氮的分解代谢。数据表明，这可能是由于胰高血糖素对丙氨酸反应的抑制所致。
