ENERGY-EXPENDITURE BY DOUBLY LABELED WATER - VALIDATION IN HUMANS AND PROPOSED CALCULATION
ENERGY-EXPENDITURE BY DOUBLY LABELED WATER - VALIDATION IN HUMANS AND PROPOSED CALCULATION
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DOI：
10.1152/ajpregu.1986.250.5.r823
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发表时间：
1986-05-01
影响因子：
--
通讯作者：
JEQUIER, E
中科院分区：
文献类型：
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作者：
SCHOELLER, DA;RAVUSSIN, E;JEQUIER, E
为了进一步验证用于测量人类二氧化碳产生和能量消耗的双标记水方法，我们将其与九名健康年轻成年男性的近乎连续的呼吸气体交换进行了比较。受试者被安置在呼吸室中 4 天。每个人都接受低剂量 (n = 6) 或中等剂量 (n = 3) 同位素剂量的 2H218O。低剂量和中等剂量产生5和10倍的初始2H富集。分别过量 10-3 原子百分比，初始 18O 富集度为 2 倍和 2.5 倍。分别过量10-2原子百分比。根据给药后 4 小时和 5 小时收集的唾液中的同位素稀释度计算体内总水量。 CO2 产量是通过两点法使用每个受试者进入和离开房间之前收集的尿液同位素富集度来计算的。通过同位素比质谱法测量相对于给药前样品的同位素富集度。在低同位素剂量下，双标记水将平均每日能量消耗高估了 8 .+-。 9% (SD)（范围 -7 至 22%）。在中等剂量下，差异减少至+4.+-。 5%（范围0-9%）。从一名受试者收集的连续尿液中 2H 和 18O 的同位素消除曲线显示出预期的昼夜变化，但在其他方面相当平滑。高估可能是由于对同位素分馏和同位素稀释的修正的近似造成的。提出了另一种修正方法，将高估值降低至 1%。
To further validate the doubly labeled water method for measurement of CO2 production and energy expenditure in humans, we compared it with near-continuous respiratory gas exchagne in nine healthy young adult males. Subjects were housed in a respiratory chamber for 4 days. Each received 2H218O at either a low (n = 6) or a moderate (n = 3) isotope dose. Low and moderate doses produced initial 2H enrichments of 5 and 10 .times. 10-3 atom percent excess, respectively, and initial 18O enrichments of 2 and 2.5 .times. 10-2 atom percent excess, respectively. Total body water was calculted from isotope dilution in saliva collected at 4 and 5 h after the dose. CO2 production was calculated by the two-point method using the isotopic enrichments of urines collected just before each subject entered and left the chamber. Isotope enrichments relative to predose samples were measured by isotope ratio mass spectrometry. At low isotope dose, doubly labeled water overestimated average daily energy expenditure by 8 .+-. 9% (SD) (range -7 to 22%). At moderate dose the difference was reduced to +4 .+-. 5% (range 0-9%). The isotope elimination curves for 2H and 18O from serial urines collected from one of the subjects showed expected diurnal variations but were otherwise quite smooth. The overestimate may be due to approximations in the corrections fo risotope fractionation and isotope dilution. An alternative approach to the corrections is presented that reduces the overestimate to 1%.