Département de Biologie Expérimentale, Métabolique et Clinique (EA 4466), Faculté de Pharmacie, Université Paris Descartes, 75 270, Paris Cedex 06, France.
Amino Acids. 2012 Apr;42(4):1425-33. doi: 10.1007/s00726-011-0841-2. Epub 2011 Feb 23.
Protein energy malnutrition in the elderly causes preferential loss of muscle mass which is associated with poor functional states. Leucine and citrulline are able to stimulate muscle protein synthesis in aged rats but no study has been undertaken to evaluate their effect on muscle function. Sprague-Dawley male rats aged 23 months were used in the experiment. Part of them were subjected to a dietary restriction for 12 weeks and then assigned to four groups: a group was euthanized (restricted group), and the others were refed for 1 week with either a leucine-, a citrulline-supplemented diet, or a standard diet. The other rats were fed ad libitum. Muscle mass and motor activity significantly increased during the refeeding with either leucine or citrulline (respectively, +51 and +37% for muscle mass, P < 0.05). The improvement of muscle mass and of motor activity induced by leucine and citrulline was highly associated with that of maximal tetanic isometric force (r = 0.769, P < 0.0001; r = 0.389, P < 0.05, respectively) but only leucine improved maximal tetanic isometric force (+101%, P < 0.05). In conclusion, this is the first study to demonstrate the ability of two amino acids (leucine and citrulline) to modulate muscle function.
老年人的蛋白质能量营养不良导致肌肉质量的优先损失，这与较差的功能状态有关。亮氨酸和瓜氨酸能够刺激老年大鼠的肌肉蛋白质合成，但尚未有研究评估它们对肌肉功能的影响。在实验中使用了 23 个月大的雄性 Sprague-Dawley 大鼠。其中一部分大鼠接受了 12 周的饮食限制，然后分为四组：一组被安乐死（限制组），其余组分别用添加亮氨酸或瓜氨酸的饮食或标准饮食进行 1 周的再喂养。其余大鼠自由进食。亮氨酸或瓜氨酸再喂养可显著增加肌肉质量和运动活性（分别为肌肉质量增加 51%和 37%，P < 0.05）。亮氨酸和瓜氨酸诱导的肌肉质量和运动活性的改善与最大等长强直收缩力的改善高度相关（r = 0.769，P < 0.0001；r = 0.389，P < 0.05，分别），但只有亮氨酸能提高最大等长强直收缩力（增加 101%，P < 0.05）。总之，这是第一项研究表明两种氨基酸（亮氨酸和瓜氨酸）能够调节肌肉功能。
