Hankard R G, Hammond D, Haymond M W, Darmaun D
Nemours Children's Clinic, Jacksonville, Florida 32247, USA.
Pediatr Res. 1998 Feb;43(2):222-6. doi: 10.1203/00006450-199802000-00011.
We determined whether glutamine has a protein anabolic effect in six 8-13-y-old boys with Duchenne muscular dystrophy. Children received a 5-h i.v. infusion of L-[1-13C]leucine and L-[2-15N]glutamine in the postabsorptive state on two consecutive days while drinking: 1) flavored water on one day, and 2) the same drink mixed with L-glutamine (800 micromol x kg[-1] x h[-1]), the other day. Oral glutamine administration was associated with an 8% decrease in leucine release from protein breakdown, from 116 +/- 5 to 107 +/- 6 micromol x kg(-1) h(-1) (p < 0.01), and a 35% decrease in leucine oxidation rate from 23 +/- 2 to 15 +/- 2 micromol x kg(-1) x h(-1) (p < 0.01), resulting in no change in the nonoxidative leucine disposal, an index of protein synthesis. Whole body glutamine exchange in plasma doubled from 321 +/- 22 to 623 +/- 24 micromol x kg(-1) x h(-1), p < 0.01, but glutamine from protein degradation and glutamine de novo synthesis both decreased (91 +/- 4 versus 84 +/- 5 micromol x kg(-1) x h(-1), p < 0.01, and 230 +/- 21 versus 163 +/- 25 micromol x kg(-1) x (h-1), p = 0.02, respectively). These data suggest that acute oral glutamine administration might have a protein-sparing effect in children with Duchenne muscular dystrophy, decreasing estimates of whole body protein degradation and glutamine de novo synthesis, therefore sparing nitrogen precursors.
我们确定了谷氨酰胺对6名8至13岁的杜氏肌营养不良男孩是否具有蛋白质合成代谢作用。这些儿童在连续两天的吸收后状态下接受了5小时的静脉输注L-[1-¹³C]亮氨酸和L-[2-¹⁵N]谷氨酰胺，同时饮用：1）一天喝加味水，2）另一天喝与L-谷氨酰胺（800微摩尔×千克⁻¹×小时⁻¹）混合的相同饮品。口服谷氨酰胺与蛋白质分解产生的亮氨酸释放量减少8%有关，从116±5降至107±6微摩尔×千克⁻¹×小时⁻¹（p<0.01），亮氨酸氧化率从23±2降至15±2微摩尔×千克⁻¹×小时⁻¹（p<0.01），导致非氧化亮氨酸处置量（蛋白质合成指标）无变化。血浆中全身谷氨酰胺交换量从321±22增加到623±24微摩尔×千克⁻¹×小时⁻¹，p<0.01，但来自蛋白质降解的谷氨酰胺和谷氨酰胺从头合成均减少（分别为91±4对84±5微摩尔×千克⁻¹×小时⁻¹，p<0.01；230±21对163±25微摩尔×千克⁻¹×小时⁻¹，p = 0.02）。这些数据表明，急性口服谷氨酰胺可能对杜氏肌营养不良儿童具有蛋白质节省作用，降低全身蛋白质降解和谷氨酰胺从头合成的估计值，从而节省氮前体。
