James K A, Treloar B P
J Nutr. 1981 Oct;111(10):1797-804. doi: 10.1093/jn/111.10.1797.
The livers of rats (190-210 g) fed casein (a phosphoprotein) or lactalbumin (non-phosphoprotein) diets (200 g protein/kg diet) were perfused for 20, 40, or 60 minutes with 5 microCi of [14C]leucine. We determined the amount of radioactivity in the protein and non-protein (free amino acid) fractions of the liver and perfusate supernatant. The wet weight, total protein and protein: DNA ratio of the livers was also determined. The livers of the group fed casein were significantly lighter and contained less protein than the lactalbumin-fed group. However, more [14C]leucine was incorporated into protein of the liver plus perfusate supernatant of the casein-fed group than the lactalbumin group. We concluded that protein metabolism in the liver of rats appears to be increased when the rats were fed a diet containing phosphoprotein as the sole source of protein.
给体重190 - 210克的大鼠喂食酪蛋白（一种磷蛋白）或乳白蛋白（非磷蛋白）日粮（日粮中蛋白质含量为200克/千克），然后用5微居里的[¹⁴C]亮氨酸对大鼠肝脏进行20、40或60分钟的灌注。我们测定了肝脏和灌注液上清液的蛋白质和非蛋白质（游离氨基酸）部分的放射性含量。还测定了肝脏的湿重、总蛋白以及蛋白与DNA的比例。喂食酪蛋白组的大鼠肝脏比喂食乳白蛋白组的明显更轻，蛋白质含量也更低。然而，与乳白蛋白组相比，喂食酪蛋白组的肝脏加灌注液上清液中掺入的[¹⁴C]亮氨酸更多。我们得出结论，当大鼠以含磷蛋白作为唯一蛋白质来源的日粮喂食时，大鼠肝脏中的蛋白质代谢似乎会增强。
