Regulation of total and myofibrillar protein breakdown in rat extensor digitorum longus and soleus muscle incubated flaccid or at resting length.
Regulation of total and myofibrillar protein breakdown in rat extensor digitorum longus and soleus muscle incubated flaccid or at resting length.
复制标题
大鼠趾长伸肌和比目鱼肌在松弛或静息状态下的总蛋白分解和肌原纤维蛋白分解的调节。
DOI：
10.1042/bj2670037
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Fischer,JE
中科院分区：
文献类型：
--
作者：
Hasselgren,PO;Hall-Angerås,M;Angerås,U;Benson,D;James,JH;Fischer,JE
本研究的特点是总的和肌原纤维蛋白的分解率在体外经常使用的肌肉制剂，即孵育伸趾长肌（EDL）和比目鱼肌（SOL）的年轻大鼠的肌肉。通过测定酪氨酸和3-甲基组氨酸（3-MH）的孵育肌肉的净产量来评估总蛋白和肌原纤维蛋白的分解率。通过高效液相色谱法测定两种氨基酸。总的和肌原纤维蛋白质的分解率均高于SOL比在EDL肌肉，并通过孵育保持在静息长度的肌肉，而不是松弛下降。禁食72小时后，总蛋白质分解（即酪氨酸释放）增加了73%和138%，分别在松弛和休息长度培养的EDL肌肉。SOL肌肉的酪氨酸净产量没有显着改变禁食。与此相反，肌原纤维蛋白降解（即3-MH释放）显着增加禁食在两块肌肉。当组织在1 munit/ml胰岛素存在下孵育时，总蛋白质分解率被抑制17- 20%，并且在松弛孵育的肌肉中或在静息长度下对激素的反应是相似的。与此相反，肌原纤维蛋白的分解率没有改变胰岛素在任何肌肉制剂。这些结果支持肌原纤维蛋白和非肌原纤维蛋白的个体调节的概念，以及不同类型骨骼肌中各种条件对蛋白质分解的不同影响。因此，测定红肌和白色肌中酪氨酸和3-MH的产生对于更完整地理解骨骼肌中的蛋白质调节是重要的。
The present study characterized total and myofibrillar protein breakdown rates in a muscle preparation frequently used in vitro, i.e. incubated extensor digitorum longus (EDL) and soleus (SOL) muscles of young rats. Total and myofibrillar protein breakdown rates were assessed by determining net production by the incubated muscles of tyrosine and 3-methylhistidine (3-MH) respectively. Both amino acids were determined by h.p.l.c. Both total and myofibrillar protein breakdown rates were higher in SOL than in EDL muscles and were decreased by incubating the muscles maintained at resting length, rather than flaccid. After fasting for 72 h, total protein breakdown (i.e. tyrosine release) was increased by 73% and 138% in EDL muscles incubated flaccid and at resting length respectively. Net production of tyrosine by SOL muscle was not significantly altered by fasting. In contrast, myofibrillar protein degradation (i.e. 3-MH release) was markedly increased by fasting in both muscles. When tissue was incubated in the presence of 1 munit of insulin/ml, total protein breakdown rate was inhibited by 17-20%, and the response to the hormone was similar in muscles incubated flaccid or at resting length. In contrast, myofibrillar protein breakdown rate was not altered by insulin in any of the muscle preparations. The results support the concepts of individual regulation of myofibrillar and non-myofibrillar proteins and of different effects of various conditions on protein breakdown in different types of skeletal muscle. Thus determination of both tyrosine and 3-MH production in red and white muscle is important for a more complete understanding of protein regulation in skeletal muscle.