SUPPLEMENTAL ESSENTIAL AMINO-ACIDS AUGMENT THE SOMATOMEDIN-C INSULIN-LIKE GROWTH FACTOR-I RESPONSE TO REFEEDING AFTER FASTING
SUPPLEMENTAL ESSENTIAL AMINO-ACIDS AUGMENT THE SOMATOMEDIN-C INSULIN-LIKE GROWTH FACTOR-I RESPONSE TO REFEEDING AFTER FASTING
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DOI：
10.1016/0026-0495(85)90230-6
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发表时间：
1985-01-01
影响因子：
9.8
通讯作者：
UNDERWOOD, LE
中科院分区：
文献类型：
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作者：
CLEMMONS, DR;SEEK, MM;UNDERWOOD, LE
血浆生长调节素C（Sm-C）/胰岛素样生长因子I（IGF-I）浓度反映了营养摄入量控制引起的氮平衡变化。为评价Sm-C/IGF-I对限制蛋白质饮食（其中氮源补充必需氨基酸）的反应，6名正常成年人禁食5天，然后再喂由35 kcal/kg和0.48 g蛋白质/kg体重组成的饮食9天。在一种饮食中，80%的N是作为必需氨基酸提供的，而在另一种饮食中，80%是作为非必需氨基酸提供的。在第一个禁食/再喂养周期后，在重复禁食之前进食对照饮食2周，并摄入另一种试验饮食。重新喂食的饮食是随机的。血浆Sm-C/IGF-I从禁食前的平均值1.64 ±下降。0.24 U/ml（平均值±. 1 SEM [平均值的标准误差]）至0.67 ±。0.18（P < 0.001），上升至1.41 ± 0.001。0.19 U/ml（P < 0.001）。当同样的受试者重新喂食80%的N以非必需氨基酸形式存在的饮食时，血浆Sm-C/iGF-I浓度从0.74 ± 0.05升高到0.74 ± 0.05。0.17 1.15U/ml（P < 0.01）。这种增加明显低于摄入补充必需氨基酸的饮食后观察到的增加（0.74 ± 0.95）。0.10 U/ml vs. 0.40 . ±. 0.11 U/ml P < 0.02）。氮平衡估计值的变化与Sm-C/IGF-I的变化相关（r = 0.81）。在补充必需氨基酸的饮食中，平均每日估计的氮平衡为-1.62。0.20 g/天，而喂食非必需氨基酸含量高的饮食的受试者具有显著更负的估计N平衡（-3.4 . ±. 0.18 g/天，P < 0.001）。血清前白蛋白浓度也随着禁食而下降，随着再喂养而上升。与Sm-C/IGF-I一样，当受试者重新喂食补充必需氨基酸的饮食时，前白蛋白浓度的增加显著更大。血浆Sm-C/IGF-I的测定可作为监测营养素摄入反应的有效方法，并有助于在限制蛋白质摄入时合理安排氮平衡膳食。
Plasma somatomedin C (Sm-C)/insulin-like growth factor I (IGF-I) concentrations reflect changes in N balance induced by manipulation of nutrient intake. To assess the Sm-C/IGF-I response to refeeding a protein restricted diet in which the N source was supplemented with essential amino acids, 6 normal adults were fasted for 5 days, then refed for 9 days diets consisting of 35 kcals/kg and 0.48 g protein/kg body wt. In one diet, 80% of the N was supplied as essential amino acids, and in the other, 80% was supplied as nonessential amino acids. Following the first fast/refeed cycle, a control diet was eaten for 2 wk before the fast was repeated and the other test diet was ingested. The refeeding diets were given a random order. Plasma Sm-C/IGF-I fell from a pre-fast mean of 1.64 .+-. 0.24 U/ml (mean .+-. 1 SEM [standard error of the mean]) to 0.67 .+-. 0.18 (P < 0.001) following fasting, and rose to 1.41 .+-. 0.19 U/ml (P < 0.001) following ingestion of the diet with supplemental essential amino acids. When the same subjects were refed a diet in which 80% of the N was in the form of nonessential amino acids, the plasma Sm-C/iGF-I concentrations rose from 0.74 .+-. 0.17 to 1.15 U/ml (P < 0.01). This increase was significantly less than that observed after ingestion of the essential amino acids supplemented diet (0.74 .+-. 0.10 U/ml vs. 0.40 .+-. 0.11 U/ml P < 0.02). Changes in estimated N balance correlated with changes in Sm-C/IGF-I (r = 0.81). The mean daily estimated N balance on the diet with supplemental essential amino acids was -1.62 .+-. 0.20 g/day, whereas subjects fed the diet high in nonessential amino acids had significantly more negative estimated N balance (-3.4 .+-. 0.18 g/day, P < 0.001). Serum prealbumin concentrations also declined with fasting and rose with refeeding. As with Sm-C/IGF-I the increase in prealbumin concentrations was significantly greater when subjects were refed the diet supplemented with essential amino acids. Plasma Sm-C/IGF-I measurements may be a useful method for monitoring the response to nutritient intake, and may be helpful in contructing diets which provide more favroable N balance during protein restriction.