Morrison P R, Montgomery J A, Wong T S, Booth F W
Biochem J. 1987 Jan 1;241(1):257-63. doi: 10.1042/bj2410257.
It is known that immobilization of the rat hindlimb by plaster casting leads to muscle atrophy and loss of muscle protein. In the present study, immobilization of the rat hindlimb for 6 h resulted in a significant 27% decrease in the absolute rate of cytochrome c synthesis in the red quadriceps muscle, without any change in the relative amount of cytochrome c mRNA. Cytochrome c mRNA in normal red quadriceps muscle was observed to be of four different lengths (1400, 1050, 650 and 580 bases). After 7 days of immobilization, the absolute rate of cytochrome c synthesis remained depressed and cytochrome c mRNA decreased by 40%; each of the cytochrome c mRNAs decreased, with a preferential disappearance of the 1050- and 1400-base lengths. Immobilization was ended on day 7, and the atrophied muscle was allowed to recover. At day 4 of recovery, the absolute rate of cytochrome c synthesis was 92% higher and the amount of cytochrome c mRNA had returned to control values. The abundances of the 1050- and 1400-base cytochrome c mRNAs had increased more than the shorter cytochrome c mRNAs, so that they were higher than control values. It appears that acute decreases in contractile activity of the red quadriceps muscle alter cytochrome c synthesis rates via translational or post-translational mechanisms, whereas chronic periods of modified contractile activity alter its synthesis rate via pre-translational mechanisms.
已知通过石膏固定大鼠后肢会导致肌肉萎缩和肌肉蛋白流失。在本研究中，将大鼠后肢固定6小时导致红色股四头肌中细胞色素c合成的绝对速率显著降低27%，而细胞色素c mRNA的相对量没有任何变化。正常红色股四头肌中的细胞色素c mRNA观察到有四种不同长度（1400、1050、650和580个碱基）。固定7天后，细胞色素c合成的绝对速率仍然降低，细胞色素c mRNA减少了40%；每种细胞色素c mRNA都减少了，1050和1400碱基长度的优先消失。固定在第7天结束，让萎缩的肌肉恢复。在恢复的第4天，细胞色素c合成的绝对速率高出92%，细胞色素c mRNA的量已恢复到对照值。1050和1400碱基的细胞色素c mRNA的丰度增加幅度大于较短的细胞色素c mRNA，因此高于对照值。似乎红色股四头肌收缩活性的急性降低通过翻译或翻译后机制改变细胞色素c的合成速率，而收缩活性改变的慢性时期则通过翻译前机制改变其合成速率。
