ABSTRACT A novel doubly [1-13C, α-15NH2]-labelled amino acid method (DLAAM) is presented for the determination of the CO2 production (RCO2) and energy expenditure in humans. This method is based on the simultaneous administration of [1-13C]glycine and [15N]glycine followed by the measurement of excretion kinetics of breath 13CO2 and urinary 15N. The basic idea of the DLAAM is that the unknown 13C recovery RF(13C) of the 1-13C amino acid, essential for the calculation of the net CO2 production, can be approximated by the easily measureable 15N recovery RF(15N) of the α-15NH2 labelled amino acid. In four healthy adult men (76–97 kg) the DLAAM was tested parallel to the IC and in one man (74 kg) parallel to the DLWM. Using the approximation RF(13C) ≈ RF(15N) the RCO2 (in l CO2 d–1) was calculated to 387.0 ± 30.3 (DLAAM) vs. 382.8 ± 22.6. (IC). The Bland–Altman plot shows that the difference between the DLAAM and IC of individual RCO2 is within the 95 % confidence interval (mean ± 2 SD): +4.3 ± 37.5 l CO2 d–1. We conclude that the DLAAM and IC may be used interchangeably. The physical activity level (PAL) was calculated based on the DLAAM vs. DLWM to about 1.5.

中文翻译：

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一种用于测量人体能量和蛋白质代谢的新型双标记 13C、15N 氨基酸方法

摘要提出了一种新的双 [1-13C, α-15NH2] 标记氨基酸方法 (DLAAM)，用于测定人类的 CO2 产量 (RCO2) 和能量消耗。该方法基于同时施用 [1-13C] 甘氨酸和 [15N] 甘氨酸，然后测量呼吸 13CO2 和尿 15N 的排泄动力学。DLAAM 的基本思想是 1-13C 氨基酸的未知 13C 回收率 RF(13C)，对于计算净 CO2 产量必不可少，可以通过易于测量的 α 的 15N 回收率 RF(15N) 来近似-15NH2标记的氨基酸。在四名健康成年男性（76-97 公斤）中，DLAAM 与 IC 平行测试，一名男性（74 公斤）与 DLWM 平行测试。使用近似值 RF(13C) ≈ RF(15N)，计算出的 RCO2（在 l CO2 d–1 中）为 387.0 ± 30.3 (DLAAM) 与 382.8 ± 22.6。（我知道了）。Bland-Altman 图显示个体 RCO2 的 DLAAM 和 IC 之间的差异在 95% 置信区间内（平均值 ± 2 SD）：+4.3 ± 37.5 l CO2 d–1。我们得出结论，DLAAM 和 IC 可以互换使用。基于 DLAAM 与 DLWM 计算的身体活动水平 (PAL) 约为 1.5。