Chi M M, Manchester J K, Lowry O H
Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Aviat Space Environ Med. 1998 Jun;69(6 Suppl):A9-11.
The enzyme composition of different muscle types vary greatly, leading to different changes of enzyme level caused by exposure to various stimuli.
Male Wistar rats were centrifuged at 2G in a 12-ft radius centrifuge for 14 d. Tibialis anterior (TA) and soleus muscles from four centrifuge and four control rats were analyzed for three enzymes characteristic of fast twitch muscles (phosphofructokinase, glycerol-3-phosphate dehydrogenase, and pyruvate kinase), and four enzymes characteristic of slow twitch muscles (hexokinase, mitochondrial thiolase, B-hydroxyacyl CoA dehydrogenase, and citrate synthase).
The centrifuged TA muscles lost 15% of their weight; the corresponding soleus muscles gained 4%. Calculated on the basis of dry weight, the fast twitch enzyme activities were reduced 3-15% in the TA muscles but increased 10-23% in the soleus muscles. The slow twitch enzymes were reduced 18-30% in TA muscles but were almost unchanged in the soleus muscles. When calculated on the basis of total muscle weight, all of the enzymes in TA muscles were significantly reduced by centrifugation. In contrast, in soleus muscles, on the basis of total muscle weight, centrifugation caused an average increase of 22% in the fast twitch enzymes but only marginal changes in the slow twitch enzymes.
不同肌肉类型的酶组成差异很大，导致暴露于各种刺激时酶水平发生不同变化。
将雄性Wistar大鼠置于半径为12英尺的离心机中以2G离心14天。对4只离心大鼠和4只对照大鼠的胫前肌（TA）和比目鱼肌进行分析，检测快肌特征性的三种酶（磷酸果糖激酶、甘油-3-磷酸脱氢酶和丙酮酸激酶）以及慢肌特征性的四种酶（己糖激酶、线粒体硫解酶、β-羟酰基辅酶A脱氢酶和柠檬酸合酶）。
离心后的TA肌重量减轻了15%；相应的比目鱼肌重量增加了4%。以干重计算，TA肌中快肌酶活性降低了3 - 15%，而比目鱼肌中增加了10 - 23%。TA肌中慢肌酶活性降低了18 - 30%，而比目鱼肌中几乎没有变化。以总肌肉重量计算，离心使TA肌中的所有酶均显著降低。相比之下，以总肌肉重量计算，离心使比目鱼肌中的快肌酶平均增加了22%，而慢肌酶仅有微小变化。
