Hong S O, Layman D K
J Nutr. 1984 Jul;114(7):1204-12. doi: 10.1093/jn/114.7.1204.
Weanling rats were used to examine the role of leucine in in vitro protein turnover in skeletal muscles. In three experiments, rats were subjected to 24 or 72 hours of food deprivation or 5 days of consuming a protein-free diet or injection of streptozotocin. The soleus and extensor digitorum longus muscles were removed and utilized for measures of protein synthesis or degradation by using the isolated, incubated muscle technique of Li et al. These experiments demonstrate that supplementation of the incubation media with 0.5 mM leucine stimulates protein synthesis in these catabolic muscles and that during total starvation the stimulation decreases as the severity of the condition increases. Leucine supplementation failed to affect protein degradation in these skeletal muscles. This study demonstrates that the branched-chain amino acid leucine has the potential to stimulate protein synthesis in skeletal muscles, at least under specific catabolic conditions, but does not affect protein degradation in skeletal muscles under the conditions studied.
断奶大鼠被用于研究亮氨酸在骨骼肌体外蛋白质周转中的作用。在三个实验中，大鼠分别经历24或72小时的食物剥夺、5天的无蛋白饮食或注射链脲佐菌素。切除比目鱼肌和趾长伸肌，采用Li等人的离体孵育肌肉技术来测量蛋白质合成或降解。这些实验表明，在孵育培养基中添加0.5 mM亮氨酸可刺激这些分解代谢肌肉中的蛋白质合成，并且在完全饥饿期间，随着饥饿程度的增加，这种刺激作用会减弱。亮氨酸补充剂未能影响这些骨骼肌中的蛋白质降解。本研究表明，至少在特定的分解代谢条件下，支链氨基酸亮氨酸有刺激骨骼肌蛋白质合成的潜力，但在所研究的条件下不影响骨骼肌中的蛋白质降解。
