Skeletal muscle myofibrillar and sarcoplasmic protein synthesis rates are affected differently by altitude-induced hypoxia in native lowlanders.
Skeletal muscle myofibrillar and sarcoplasmic protein synthesis rates are affected differently by altitude-induced hypoxia in native lowlanders.
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DOI：
10.1371/journal.pone.0015606
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发表时间：
2010-12-20
期刊：
影响因子：
3.7
通讯作者：
Lundby C
中科院分区：
文献类型：
--
作者：
Holm L;Haslund ML;Robach P;van Hall G;Calbet JA;Saltin B;Lundby C
作为低压低氧暴露的结果，经常报告骨骼肌萎缩。潜在的机制已被认为涉及蛋白质合成的减少，以保存O2。为了挑战这一假设的目的，我们在9名健康男性受试者中应用了1- 13 C-亮氨酸的预充，恒定输注，这些受试者在海平面和随后在高海拔（4559 m）经过7-9天的适应。在两种实验条件之前控制身体活动水平和食物和能量摄入，目的是使这些混杂因素标准化。在4小时试验期间每小时收集血液样品和呼气样品，并在过夜禁食状态下在示踪剂引发后1小时和4小时获得股外侧肌活检。肌原纤维蛋白质合成率增加了一倍;海平面时为0.041±0.018，适应高海拔时为0.080±0.018%·hr-1（p<0.05）。相反，肌浆蛋白合成率不受海拔暴露的影响;海平面为0.052±0.019，而海拔为0.059±0.010%·hr-1（p>0.05）。观察到全身蛋白质动力学增加的趋势：降解速率从海平面的2.51±0.21升高到高海拔的2.73±0.13 µmol·kg−1·min−1（p = 0.05），合成速率相似;海平面为2.24±0.20，高海拔为2.43±0.13 µmol·kg−1·min−1（p>0.05）。 我们的结论是，由于蛋白质周转率升高，全身氨基酸通量增加。静止状态下的骨骼肌肌收缩蛋白合成率随高原低氧的升高而升高，而肌浆蛋白合成率则不受低氧的影响。这些变化的反应可能会导致在长期接触过程中出现不同的适应。
As a consequence to hypobaric hypoxic exposure skeletal muscle atrophy is often reported. The underlying mechanism has been suggested to involve a decrease in protein synthesis in order to conserve O2. With the aim to challenge this hypothesis, we applied a primed, constant infusion of 1-13C-leucine in nine healthy male subjects at sea level and subsequently at high-altitude (4559 m) after 7–9 days of acclimatization. Physical activity levels and food and energy intake were controlled prior to the two experimental conditions with the aim to standardize these confounding factors. Blood samples and expired breath samples were collected hourly during the 4 hour trial and vastus lateralis muscle biopsies obtained at 1 and 4 hours after tracer priming in the overnight fasted state. Myofibrillar protein synthesis rate was doubled; 0.041±0.018 at sea-level to 0.080±0.018%⋅hr−1 (p<0.05) when acclimatized to high altitude. The sarcoplasmic protein synthesis rate was in contrast unaffected by altitude exposure; 0.052±0.019 at sea-level to 0.059±0.010%⋅hr−1 (p>0.05). Trends to increments in whole body protein kinetics were seen: Degradation rate elevated from 2.51±0.21 at sea level to 2.73±0.13 µmol⋅kg−1⋅min−1 (p = 0.05) at high altitude and synthesis rate similar; 2.24±0.20 at sea level and 2.43±0.13 µmol⋅kg−1⋅min−1 (p>0.05) at altitude. We conclude that whole body amino acid flux is increased due to an elevated protein turnover rate. Resting skeletal muscle myocontractile protein synthesis rate was concomitantly elevated by high-altitude induced hypoxia, whereas the sarcoplasmic protein synthesis rate was unaffected by hypoxia. These changed responses may lead to divergent adaptation over the course of prolonged exposure.
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影响因子：
5.5
作者：
Miller, BF;Olesen, JL;Rennie, MJ
通讯作者：
Rennie, MJ
氨基酸和胰岛素对人类肌肉中信号传导，泛素连接酶和蛋白质更新的作用之间的分离。
DOI：
10.1152/ajpendo.90411.2008
发表时间：
2008-09
期刊：
American journal of physiology. Endocrinology and metabolism
影响因子：
--
作者：
Greenhaff PL;Karagounis LG;Peirce N;Simpson EJ;Hazell M;Layfield R;Wackerhage H;Smith K;Atherton P;Selby A;Rennie MJ
通讯作者：
Rennie MJ
DOI：
10.1249/01.mss.0000222836.66391.35
发表时间：
2006-06-01
期刊：
MEDICINE AND SCIENCE IN SPORTS AND EXERCISE
影响因子：
--
作者：
Imoberdorf, Reinhard;Garlick, Peter J.;Ballmer, Peter E.
通讯作者：
Ballmer, Peter E.
影响因子：
3.3
作者：
KAYSER, B;ACHESON, K;CERRETELLI, P
通讯作者：
CERRETELLI, P
影响因子：
4.1
作者：
PREEDY, VR;SUGDEN, PH
通讯作者：
SUGDEN, PH