Henriksson J, Chi M M, Hintz C S, Young D A, Kaiser K K, Salmons S, Lowry O H
Am J Physiol. 1986 Oct;251(4 Pt 1):C614-32. doi: 10.1152/ajpcell.1986.251.4.C614.
Twenty-one enzymes of different metabolic systems were measured in the rabbit fast-twitch tibialis anterior (TA) muscle after electrical stimulation (10 Hz, 24 h/day) for 1 day to 10 wk. Nine analytical methods are either new, (3-oxoacid CoA-transferase, branched-chain-amino-acid aminotransferase, carnitine acetyltransferase, thiolase), improved (glutamate dehydrogenase, glycogen synthase, adenylic acid deaminase), or specially adapted (hexokinase, phosphoglucomutase). The activities (based on protein) of 12 mitochondrial or partly mitochondrial enzymes were lower in control TA than in control (slow) soleus (30-84% of soleus level). After 2 wk, 11 of these had surpassed the control soleus level. Maximal increases (3- to 14-fold) occurred after 2-5 wk, and thereafter six of the enzymes declined, whereas the other five maintained or increased their levels. Five glycolytic and two high-energy phosphate transfer enzymes, originally much higher in control TA than in control soleus, decreased gradually to levels at 8-10 wk only 27-123% higher than in soleus. Noncollagen protein concentration dropped 46%, explained largely by a sixfold increase in extracellular (chloride) space and a modest increase in collagen. The data constitute strong evidence for coordinate regulation of (mainly cytosolic) enzymes of glycolysis, glycogenolysis, gluconeogenesis, and high-energy phosphate transfer. Changes in the (mainly mitochondrial) enzymes of oxidative metabolism were more divergent, partly because of a hitherto undescribed secondary phase in the metabolic response. This phase may reflect a lower energy consumption in muscles adapted to continuous activity.
对兔的快肌胫骨前肌（TA）进行电刺激（10赫兹，每天24小时），持续1天至10周，之后测定了不同代谢系统的21种酶。九种分析方法要么是新的（3-氧代酸辅酶A转移酶、支链氨基酸转氨酶、肉碱乙酰转移酶、硫解酶），要么是改进的（谷氨酸脱氢酶、糖原合酶、腺苷酸脱氨酶），要么是特别适配的（己糖激酶、磷酸葡萄糖变位酶）。对照TA中12种线粒体或部分线粒体酶基于蛋白质的活性低于对照（慢肌）比目鱼肌（为比目鱼肌水平的30%-84%）。2周后，其中11种酶超过了对照比目鱼肌的水平。最大增幅（3至14倍）出现在2至5周后，此后六种酶活性下降，而另外五种酶保持或提高了其水平。五种糖酵解酶和两种高能磷酸转移酶，最初在对照TA中比对照比目鱼肌高得多，逐渐下降至8至10周时仅比目鱼肌高27%-123%的水平。非胶原蛋白浓度下降了46%，这主要是由于细胞外（氯离子）空间增加了六倍以及胶原蛋白适度增加所致。这些数据为糖酵解、糖原分解、糖异生和高能磷酸转移（主要是胞质）酶的协同调节提供了有力证据。氧化代谢（主要是线粒体）酶的变化更为分散，部分原因是代谢反应中存在一个迄今未描述的第二阶段。这个阶段可能反映了适应持续活动的肌肉中较低的能量消耗。
