Melville S, McNurlan M A, Calder A G, Garlick P J
Rowett Research Institute, Aberdeen, Scoutland, United Kingdom.
Cancer Res. 1990 Feb 15;50(4):1125-31.
We have examined the responses of energy and protein metabolism to nutrient intake in nine patients with lung carcinoma, of whom none were cachexic and only one had distant metastases, compared with nine control patients for elective aneurysm surgery, who were comparable in terms of age, body mass index, and smoking habits. Whole-body protein turnover and leucine oxidation were assessed by primed continuous infusion of L-[13C]leucine. Indirect calorimetry was used to determine energy expenditure and rates of carbohydrate and fat utilization. Lean body mass (LBM) was estimated from dilution of deuterium oxide. Measurements were made over an 8-h period, including 4 h postabsorptive followed by 4 h of feeding, during which small hourly meals were consumed. In the post-absorptive state, the rate of incorporation of leucine into protein was higher in the cancer group (mean +/- SD, cancer versus control: 102 +/- 21 versus 86 +/- 8 mumol/kg LBM/h, P less than 0.05), as was the release of leucine by protein degradation (126 +/- 19 versus 110 +/- 10 mumol/kg LBM/h, P less than 0.01), but there was no difference in rates of leucine oxidation (27 +/- 6 versus 27 +/- 5 mumol/kg LBM/h) or leucine balance (-25 +/- 7 versus -24 +/- 4 mumol/kg LBM/h). There were no differences between the cancer and control groups with respect to either resting energy expenditure (37.3 +/- 3.5 versus 35.2 +/- 3.8 kcal LBM/day) or the postabsorptive pattern of nutrient utilization (61 +/- 13% fat, 26 +/- 10% carbohydrate, and 13 +/- 2% protein versus 65 +/- 7%, 21 +/- 7%, and 14 +/- 2%, respectively). During feeding, leucine oxidation rose relative to the postabsorptive state, incorporation into protein remained the same, and release by protein degradation fell. Incorporation (106 +/- 20 versus 89 +/- 7 mumol/kg LBM/h, P less than 0.05) and release (59 +/- 12 versus 42 +/- 14 mumol/kg LBM/h, P less than 0.02) remained higher in the cancer group than in controls, but leucine oxidation (43 +/- 15 versus 43 +/- 12 mumol/kg LBM/h) and leucine balance (+48 +/- 10 versus +47 +/- 12 mumol/kg LBM/h) were the same. Energy expenditure during feeding increased to 43.8 +/- 5.1 versus 43.2 +/- 4.2 kcal/kg LBM/day, derived from 32 +/- 11% fat, 52 +/- 9% carbohydrate, and 16 +/- 5% protein in cancer patients and 36 +/- 7%, 48 +/- 8%, and 16 +/- 4%, respectively, in controls.(ABSTRACT TRUNCATED AT 400 WORDS)
我们研究了9例肺癌患者能量和蛋白质代谢对营养摄入的反应，这些患者均无恶病质，仅有1例有远处转移，同时与9例择期动脉瘤手术的对照患者进行比较，后者在年龄、体重指数和吸烟习惯方面具有可比性。通过静脉持续输注L-[13C]亮氨酸对全身蛋白质周转和亮氨酸氧化进行评估。采用间接测热法测定能量消耗以及碳水化合物和脂肪的利用率。通过氧化氘稀释法估算去脂体重（LBM）。测量在8小时内进行，包括4小时的空腹期，随后是4小时的进食期，在此期间每小时进食少量食物。在空腹状态下，癌症组亮氨酸掺入蛋白质的速率较高（平均值±标准差，癌症组与对照组：102±21对86±8 μmol/kg LBM/h，P<0.05），蛋白质降解释放的亮氨酸速率也较高（126±19对110±10 μmol/kg LBM/h，P<0.01），但亮氨酸氧化速率（27±6对27±5 μmol/kg LBM/h）或亮氨酸平衡（-25±7对-24±4 μmol/kg LBM/h）无差异。癌症组和对照组在静息能量消耗（37.3±3.5对35.2±3.8 kcal LBM/天）或空腹期营养利用模式（脂肪61±13%、碳水化合物26±10%、蛋白质13±2%对分别为65±7%、21±7%、14±2%）方面均无差异。进食期间，亮氨酸氧化相对于空腹状态升高，掺入蛋白质保持不变，蛋白质降解释放下降。癌症组的掺入（106±20对89±7 μmol/kg LBM/h，P<0.05）和释放（59±12对42±14 μmol/kg LBM/h，P<0.02）仍高于对照组，但亮氨酸氧化（43±15对43±12 μmol/kg LBM/h）和亮氨酸平衡（+48±10对+47±12 μmol/kg LBM/h）相同。进食期间癌症患者的能量消耗增加至43.8±5.1对43.2±4.2 kcal/kg LBM/天，分别来自32±11%的脂肪、52±9%的碳水化合物和16±5%的蛋白质，对照组分别为36±7%、48±8%和16±4%。（摘要截选至400字）
