PHYSIOLOGICAL HYPERINSULINEMIA STIMULATES PROTEIN-SYNTHESIS AND ENHANCES TRANSPORT OF SELECTED AMINO-ACIDS IN HUMAN SKELETAL-MUSCLE
PHYSIOLOGICAL HYPERINSULINEMIA STIMULATES PROTEIN-SYNTHESIS AND ENHANCES TRANSPORT OF SELECTED AMINO-ACIDS IN HUMAN SKELETAL-MUSCLE
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DOI：
10.1172/jci117731
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发表时间：
1995-02-01
影响因子：
15.9
通讯作者：
WOLFE, RR
中科院分区：
文献类型：
--
作者：
BIOLO, G;FLEMING, RYD;WOLFE, RR
我们研究了胰岛素对健康志愿者肌肉蛋白质代谢的合成代谢作用的机制，使用稳定同位素示踪氨基酸。肌肉蛋白质合成、分解和氨基酸转运的计算基于腿部动静脉导管插入术和肌肉活检获得的数据。将胰岛素（0.15 mU/min/100 ml腿）输注至股动脉，以增加股静脉胰岛素浓度（从10 +/-2至77 +/-9 mu U/ml），同时全身扰动最小。胰岛素治疗后，组织游离必需氨基酸浓度降低（P <0.05）。肌肉蛋白质的合成率（乘积法）在胰岛素治疗后从0.0401 ± 0.0072%/h增加到0.0677 ± 0.0101%/h（P <0.01）。与此观察结果一致，细胞内苯丙氨酸和赖氨酸的蛋白质合成利用率（动静脉平衡法）也分别从40 +/-8增加到59 +/-8（P <0.05）和从219 +/-21增加到298 +/-37（P <0.08）nmol/min/100 ml腿。蛋白质分解释放的苯丙氨酸，亮氨酸和赖氨酸没有显着修改胰岛素。局部高胰岛素血症使亮氨酸、赖氨酸和丙氨酸的内向转运速率分别从164 +/-22增加到200 +/-25，从126 +/-11增加到221 +/-30，从403 +/-64增加到595 +/-106 nmol/min（P <0.05）。苯丙氨酸的转运没有显著变化。我们的结论是，胰岛素促进肌肉合成代谢，主要是通过刺激蛋白质合成，而与跨膜转运的任何影响无关。
We have investigated the mechanisms of the anabolic effect of insulin on muscle protein metabolism in healthy volunteers, using stable isotopic tracers of amino acids. Calculations of muscle protein synthesis, breakdown, and amino acid transport were based on data obtained with the leg arteriovenous catheterization and muscle biopsy. Insulin was infused (0.15 mU/min per 100 ml leg) into the femoral artery to increase femoral venous insulin concentration (from 10 +/- 2 to 77 +/-9 mu U/ml) with minimal systemic perturbations. Tissue concentrations of free essential amino acids decreased (P < 0.05) after insulin. The fractional synthesis rate of muscle protein (precursor-product approach) increased (P < 0.01) after insulin from 0.0401 +/- 0.0072 to 0.0677 +/- 0.0101%/h. Consistent with this observation, rates of utilization for protein synthesis of intracellular phenylalanine and lysine (arteriovenous balance approach) also increased from 40 +/- 8 to 59 +/- 8 (P < 0.05) and from 219 +/- 21 to 298 +/- 37 (P < 0.08) nmol/min per 100 ml leg, respectively. Release from protein breakdown of phenylalanine, leucine, and lysine was not significantly modified by insulin. Local hyperinsulinemia increased (P < 0.05) the rates of inward transport of leucine, lysine, and alanine, from 164 +/- 22 to 200 +/- 25, from 126 +/- 11 to 221 +/- 30, and from 403 +/- 64 to 595 +/- 106 nmol/min per 100 ml leg, respectively. Transport of phenylalanine did not change significantly. We conclude that insulin promoted muscle anabolism, primarily by stimulating protein synthesis independently of any effect on transmembrane transport.