WHOLE BODY AND MUSCLE PROTEIN METABOLISM ARE NOT AFFECTED BY ACUTE DEVIATIONS

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 背景：在量化蛋白质动力学之前，老年人蛋白质摄入量的严重偏差可能解释了关于老年人对肌肉蛋白质合成和蛋白分解速率的影响的争议。目的：我们假设，来自习惯性摄入的蛋白质摄入量的急剧减少与肌肉蛋白质合成减少和较高的蛋白水解率有关，而从习惯性摄取的蛋白质摄入量的急剧增加与肌肉蛋白质合成和较低的蛋白质水解率有关。设计：在112名居住在社区的65-90岁健康男性中，我们量化了参与者在摄入3d受控研究膳食(0.9-1.1g蛋白质/kg/d)后的静息全身1，2-13C2-亮氨酸动力学、肌肉混合蛋白部分合成率(FSR)和肌肉蛋白酶体蛋白水解酶活性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Background: Acute deviations in protein intake prior to quantifying protein kinetics in older humans may explain the controversy over the effects of older age on muscle protein synthesis and proteolysis rates. Objective: We hypothesized that an acute decrease in protein intake from habitual intake is associated with lower muscle protein synthesis and higher proteolysis rates, while an acute increase in protein intake from habitual is associated with higher muscle protein synthesis and lower proteolysis rates. Design: In 112 community-dwelling healthy 65-90 year old men, we quantified resting whole body 1,2-13C2-leucine kinetics, muscle mixed protein fractional synthesis rates (FSR), and muscle proteasome proteolytic enzyme activities after participants consumed 3 d controlled research meals (0.9-1.1 g protein/kg/d) that contained more or less protein than they habitually consumed.