Studies on the time-course of ethanol's acute effects on skeletal muscle protein synthesis: comparison with acute changes in proteolytic activity.
Studies on the time-course of ethanol's acute effects on skeletal muscle protein synthesis: comparison with acute changes in proteolytic activity.
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乙醇对骨骼肌蛋白质合成的急性影响的时间过程研究：与蛋白水解活性的急性变化进行比较。
DOI：
10.1111/j.1530-0277.1997.tb03841.x
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
V. Preedy
中科院分区：
文献类型：
--
作者：
M. Reilly;David Mantle;Peter J. Richardson;Jonathan R. Salisbury;Jenny Jones;T. Peters;V. Preedy
在年轻雄性Wistar大鼠（150 g）中进行了乙醇对骨骼肌蛋白质合成和蛋白酶活性影响的研究，在单次腹腔内给予75 mmol乙醇/kg体重后长达24 h。在20分钟时，平均血液乙醇水平为448 mg/dl。这一水平稳步下降到零，通过以下24 hr. Comparing对喂养的对照组，总蛋白质，RNA和DNA含量显着减少，只看到24小时后，在所有骨骼肌研究：变化更显着的肌肉含有大比例的II型纤维。在跖肌中，与对照盐水注射大鼠相比，蛋白质合成的分数速率（ks，%/天）在给药后20分钟没有下降，但在1小时后降低了23%（p < 0.001），在24小时后降低了63%（p < 0.001）。这种影响与饮食摄入无关，因为与成对喂养组相比，24小时乙醇处理的大鼠仍显示蛋白质合成分数率降低52%（p < 0.001）。在24小时时，在响应于乙醇的比目鱼肌中观察到ks的较小降低（-39%，p < 0.001）。各种溶酶体和非溶酶体蛋白酶在跖肌的24小时治疗的大鼠的活动没有显着影响乙醇。只有丙氨酰和三肽氨基肽酶活性显著降低（分别为26%，p < 0.05和39%，p < 0.01）。这些结果表明，在急性期的乙醇毒性的肌肉成分的变化主要与受损的蛋白质合成和细胞蛋白水解系统的贡献可能是最小的。乙醇对骨骼肌蛋白质代谢的影响是更大的肌肉含有占主导地位的II型纤维比那些主要含有I型纤维。乙醇对肌肉的影响可能受到24小时后激素变化的影响，因为蛋白质合成仍然受到影响，并且在这个时间点，游离血浆T3和皮质酮发生变化。
A study of the effects of ethanol on skeletal muscle protein synthesis and protease activities was carried out in young male Wistar rats (150 g) for up to 24 hr after a single intraperitoneal dose of 75 mmol of ethanol/kg of body weight. At 20 min, the mean blood ethanol levels were 448 mg/dl. This level dropped steadily to zero through the following 24 hr. Compared with pair-fed controls, significant reductions in total protein, RNA, and DNA contents were seen only after 24 hr in all skeletal muscles studied: changes were more marked in the muscles containing large proportions of type II fibers. In plantaris muscle, the fractional rate of protein synthesis (ks, %/day) did not fall 20 min after dosage but was reduced after 1 hr by 23% (p < 0.001), and by 63% after 24 hr, compared with control saline-injected rats (p < 0.001). This effect was independent of dietary intake because, compared with the pair-fed group, the 24-hr ethanol-treated rats still showed a 52% decrease in fractional rates of protein synthesis (p < 0.001). Smaller reductions in ks were seen in soleus muscles in response to ethanol at 24 hr (-39%, p < 0.001). The activities of a variety of lysosomal and nonlysosomal proteases in plantaris muscle of 24-hr treated rats were not significantly affected by ethanol. Only alanyl- and tripeptidyl-aminopeptidase activities were reduced significantly (26%, p < 0.05 and 39%, p < 0.01, respectively). These results suggest that the muscle compositional changes seen over acute periods of ethanol toxicity are predominantly associated with impaired synthesis of protein and that the contribution of cellular proteolytic systems may be minimal. The effects of ethanol on skeletal muscle protein metabolism are greater in muscles containing a predominance of type II fibers than in those containing mainly type I fibers. Ethanol's effects on muscle may be influenced by hormonal changes after 24 hr, because protein synthesis is still compromised and free plasma T3 and corticosterone are altered at this time-point.