Flugel-Link R M, Salusky I B, Jones M R, Kopple J D
Adv Exp Med Biol. 1984;167:545-55. doi: 10.1007/978-1-4615-9355-3_48.
Protein synthesis and degradation and net uptake and release of amino acids and minerals were investigated in the perfused hemicorpus of acutely uremic and control Sprague-Dawley rats. Rats underwent bilateral nephrectomy or sham surgery and were studied 30 hr after surgery. The uremic rats displayed greater urea N appearance (net urea generation), lower plasma and muscle concentrations of most amino acids, and increased muscle protein degradation as compared to control rats. Muscle protein synthesis was slightly but not significantly decreased in the uremic animals. There was greater net release of phenylalanine, tyrosine, alanine, total nonessential amino acids, total amino acids, potassium and phosphorus from the perfused hemicorpus of uremic rats and greater release of citrulline from sham rats. Muscle ATP, creatine phosphate, cyclic-AMP, and activities of cathepsin B1, cathepsin D, and alkaline protease were not different in the uremic and sham rats. These data provide evidence that acutely uremic rats sustain increased muscle protein wasting which is due to enhanced protein degradation. The increased protein degradation does not appear to be due to enhanced activities of muscle cathepsin B1, cathepsin D or alkaline protease.
在急性尿毒症和对照Sprague-Dawley大鼠的灌注半体中，研究了蛋白质合成与降解以及氨基酸和矿物质的净摄取与释放。大鼠接受双侧肾切除术或假手术，并在术后30小时进行研究。与对照大鼠相比，尿毒症大鼠表现出更高的尿素氮出现率（净尿素生成）、大多数氨基酸的血浆和肌肉浓度较低，以及肌肉蛋白质降解增加。尿毒症动物的肌肉蛋白质合成略有下降，但不显著。尿毒症大鼠灌注半体中苯丙氨酸、酪氨酸、丙氨酸、总非必需氨基酸、总氨基酸、钾和磷的净释放量更大，假手术大鼠中瓜氨酸的释放量更大。尿毒症大鼠和假手术大鼠的肌肉ATP、磷酸肌酸、环磷酸腺苷以及组织蛋白酶B1、组织蛋白酶D和碱性蛋白酶的活性没有差异。这些数据提供了证据，表明急性尿毒症大鼠维持着增加的肌肉蛋白质消耗，这是由于蛋白质降解增强所致。蛋白质降解增加似乎不是由于肌肉组织蛋白酶B1、组织蛋白酶D或碱性蛋白酶的活性增强。
