Reynolds Thomas H, Reid Pamela, Larkin Lisa M, Dengel Donald R
Department of Internal Medicine, Division of Geriatric Medicine, University of Michigan and the GRECC, Ann Arbor Veterans Affairs Healthcare System, Ann Arbor, MI, USA.
Exp Gerontol. 2004 Mar;39(3):379-85. doi: 10.1016/j.exger.2003.12.005.
The protein kinase B (PKB)/mammalian target of rapamycin (mTOR) signaling pathway is thought to play a critical role in the regulation of protein synthesis and skeletal muscle mass. The purpose of the present study was to determine the effects of voluntary wheel running on the PKB/mTOR signaling pathway in muscles from aged mice (20-22 months). The total levels of mTOR were 65% higher in gastrocnemius muscles from aged mice subjected to wheel running compared to aged sedentary mice (p-0.002) PKB phosphorlation on Ser473 was 45% higher in gastrocnemius muscles from aged mice subjected to wheel running compared to aged sedentary mice (p=0.01) The total abundance of PKB was 50% higher in gastrocnemius muscles from wheel running mice compared to aged controls (p=0.005). Three months of wheel running did not alter the total amount of p70 S6K in gastrocnemius muscle. Protein synthesis, as assessed by [(14)C]phenylalanine incorporation into protein was significantly higher in soleus muscles from aged mice subjected to wheel running compared to aged sedentary mice (p-0.001) These findings indicate the aerobic exercise training may attenuate the age-related decline in protein synthesis, a process that appears to be due, in part, to increases in mTOR and PKB.
蛋白激酶B（PKB）/雷帕霉素哺乳动物靶蛋白（mTOR）信号通路被认为在蛋白质合成和骨骼肌质量的调节中起关键作用。本研究的目的是确定自愿轮转跑步对老年小鼠（20 - 22个月）肌肉中PKB/mTOR信号通路的影响。与久坐不动的老年小鼠相比，进行轮转跑步的老年小鼠腓肠肌中mTOR的总水平高65%（p = 0.002）；与久坐不动的老年小鼠相比，进行轮转跑步的老年小鼠腓肠肌中Ser473位点的PKB磷酸化水平高45%（p = 0.01）；与老年对照小鼠相比，进行轮转跑步的小鼠腓肠肌中PKB的总丰度高50%（p = 0.005）。三个月的轮转跑步并未改变腓肠肌中p70 S6K的总量。通过[¹⁴C]苯丙氨酸掺入蛋白质来评估，与久坐不动的老年小鼠相比，进行轮转跑步的老年小鼠比目鱼肌中的蛋白质合成显著更高（p = 0.001）。这些发现表明有氧运动训练可能会减轻与年龄相关的蛋白质合成下降，这一过程似乎部分归因于mTOR和PKB的增加。
