Ogata E S, Foung S K, Holliday M A
J Nutr. 1978 May;108(5):759-65. doi: 10.1093/jn/108.5.759.
We studied the effects of acute starvation and refeeding on muscle protein synthesis and degradation in young rats. As measures of synthesis, we determined muscle RNA concentration and the rate of incorporation of [14C]leucine into skeletal muscle protein (Sm). As an estimate of nitrogen retention we measured urea production (UrP). Starvation reduced these variables significantly. One refeeding period returned Sm to control values, only partially restored RNA concentration, and increased UrP. We determined the urinary excretion rate of 3-methylhistidine (3-MH) as a measure of the rate of myofibrillar protein degradation. Excretion of 3-MH was lowest in control and highest in starved rats. Refeeding decreased 3-MH excretion to a level midway between control and starved animals. Growth was attended by high rates of synthesis and low rates of degradation. Starvation depressed synthesis and increased degradation. With refeeding, synthesis increased and degradation decreased, compared with the starved state.
我们研究了急性饥饿和再喂养对幼鼠肌肉蛋白质合成与降解的影响。作为合成的指标，我们测定了肌肉RNA浓度以及[14C]亮氨酸掺入骨骼肌蛋白（Sm）的速率。作为氮潴留的估计指标，我们测量了尿素生成量（UrP）。饥饿显著降低了这些变量。一个再喂养期使Sm恢复到对照值，仅部分恢复了RNA浓度，并增加了UrP。我们测定了3-甲基组氨酸（3-MH）的尿排泄率，以此作为肌原纤维蛋白降解速率的指标。3-MH的排泄在对照动物中最低，在饥饿大鼠中最高。再喂养使3-MH排泄降至对照动物和饥饿动物之间的中间水平。生长伴随着高合成速率和低降解速率。饥饿抑制了合成并增加了降解。与饥饿状态相比，再喂养时合成增加而降解减少。
