Sheff M F, Zacks S I
Lab Invest. 1977 Aug;37(2):216-22.
A fatal, rapidly developing progressive muscle disease of delayed onset in mice is produced by the effects of an autosomal recessive gene (MED). We recognize two stages of this disease. The earlier stage, observed between the 11th and 14th postnatal day, is characterized by structurally normal small myofibers, cessation of increase in body weight, and increasing muscular weakness, particularly of the hind limbs. The second stage is characterized by a spheromembranous degeneration of myofibers and almost complete cessation of voluntary movement. Previous studies have revealed neither anatomic abnormalities in neuromuscular junctions nor major changes in oxidative metabolism or electrolyte concentrations in striated myofibers in the early stages of the disease. In this paper we report investigations designed to determine whether the failure of growth of striated muscle in the first stage is due to a defect in muscle protein synthesis or, as has been found in muscular dystrophies, is due to an increased rate of degradation of muscle. We conclude that MED animals demonstrate a different kind of defect than that occurring in dystrophic mice. In MED mice, the failure of growth is primarily due to a diminished rate of protein synthesis.
常染色体隐性基因（MED）的作用会在小鼠中引发一种迟发性、致命且迅速发展的进行性肌肉疾病。我们认识到这种疾病有两个阶段。较早阶段出现在出生后第11天至第14天之间，其特征是结构正常的小肌纤维、体重停止增加以及肌肉无力加剧，尤其是后肢。第二阶段的特征是肌纤维的球膜样变性以及几乎完全停止自主运动。先前的研究在疾病早期既未发现神经肌肉接头的解剖学异常，也未发现横纹肌纤维中氧化代谢或电解质浓度的重大变化。在本文中，我们报告了旨在确定第一阶段横纹肌生长失败是由于肌肉蛋白质合成缺陷，还是如在肌肉营养不良中所发现的那样，是由于肌肉降解速率增加的研究。我们得出结论，MED动物表现出与营养不良小鼠不同类型的缺陷。在MED小鼠中，生长失败主要是由于蛋白质合成速率降低。
