Rumsey W L, Kendrick Z V, Starnes J W
Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104.
Exp Gerontol. 1987;22(4):271-87. doi: 10.1016/0531-5565(87)90006-4.
The capacity for energy production was evaluated in male, Fischer 344 rats as they advanced from adulthood through senescence. At 10 months of age, the animals were divided into three groups: sedentary, fed ad libitum (S); exercised by treadmill running, fed ad libitum (E); and sedentary, caloric restricted by alternate day feeding (R). Activities of selected enzymes, ADP-stimulated respiration and levels of cytochromes, were determined in homogenates of liver and gastrocnemius muscle prepared from young controls (10-month old S) and 18-, 24-, and 30-month old animals. In liver, age-linked decrements were found in the activities of 3-hydroxyacyl-CoA dehydrogenase (S, E, and R) and citrate synthase (S), and in cytochrome c content (S and E), whereas substrate-catalysed oxidations were unaffected. In the gastrocnemius muscle (S, E, and R), respiration, activities of enzymes of the Krebs cycle and glycolysis, and cytochrome content were decreased after the age of 18 months. Oxidative capacity was increased in muscle through exercise (about 40%) and in liver by food restriction (about 20%). Body and soleus muscle mass declined similarly in all groups (about 14% from 30 to 18 months of age), whereas the loss of weight in the gastrocnemius muscle was much greater (34%). The data indicate that energy metabolism in the senescent animal is competent to meet its needs and age-related declines in energy metabolism are secondary to the aging process.
在雄性Fischer 344大鼠从成年期到衰老期的过程中，对其能量产生能力进行了评估。在10个月大时，将动物分为三组：久坐不动、随意进食组（S）；通过跑步机跑步锻炼、随意进食组（E）；久坐不动、隔日喂食进行热量限制组（R）。在从年轻对照组（10个月大的S组）以及18、24和30个月大的动物制备的肝脏和腓肠肌匀浆中，测定了所选酶的活性、ADP刺激的呼吸作用以及细胞色素水平。在肝脏中，3-羟酰基辅酶A脱氢酶（S、E和R组）和柠檬酸合酶（S组）的活性以及细胞色素c含量（S和E组）随年龄增长而下降，而底物催化的氧化作用未受影响。在腓肠肌中（S、E和R组），18个月龄后呼吸作用、三羧酸循环和糖酵解酶的活性以及细胞色素含量均下降。通过运动，肌肉的氧化能力增加（约40%），通过食物限制，肝脏的氧化能力增加（约20%）。所有组的体重和比目鱼肌质量均类似下降（从30个月龄到18个月龄约下降14%），而腓肠肌的体重减轻则大得多（34%）。数据表明，衰老动物的能量代谢能够满足其需求，与年龄相关的能量代谢下降是衰老过程的次要结果。
