Chronic metabolic acidosis accelerates whole body proteolysis and oxidation in awake rats.
Chronic metabolic acidosis accelerates whole body proteolysis and oxidation in awake rats.
复制标题
慢性代谢性酸中毒会加速清醒大鼠的全身蛋白水解和氧化。
DOI：
10.1038/ki.1992.223
复制
发表时间：
1992
影响因子：
19.6
通讯作者：
England,B
中科院分区：
文献类型：
--
作者：
May,RC;Masud,T;Logue,B;Bailey,J;England,B
慢性代谢性酸中毒加速清醒大鼠全身蛋白水解和氧化。以前的工作已经证明，在体外培养慢性代谢性酸中毒大鼠的肌肉时，蛋白质水解和支链氨基酸氧化加速。本研究采用随机建模和预充连续输注L-[1- 14 C]亮氨酸，研究慢性代谢性酸中毒对长期插管清醒雄性Sprague-Dawley大鼠全身氨基酸周转和氧化的影响。酸中毒加速了全身蛋白质周转，反映在蛋白质水解增加70%和蛋白质合成增加55%。基于倒数池模型和血浆α-酮异己酸比放射性，相对于接受相同蛋白质和热量饲料的对照大鼠，慢性代谢性酸中毒大鼠的氨基酸氧化增加145%。这些变化伴随着肝支链酮酸脱氢酶（BCKAD）活性增加104%，在大鼠酸中毒，类似于先前记录的骨骼肌BCKAD活性增加引起的酸中毒。相比之下，肾BCKAD活性降低38%，酸中毒，说明存在的变化的组织特异性。我们的结论是，慢性代谢性酸中毒加速全身蛋白质周转，并影响氨基酸的重新纳入体内蛋白质通过加速氨基酸氧化。
Chronic metabolic acidosis accelerates whole body proteolysis and oxidation in awake rats. Previous work has documented an acceleration of proteolysis and branched-chain amino acid oxidation when muscles from rats with chronic metabolic acidosis were incubated in vitro. The present study examines the impact of chronic metabolic acidosis on whole body amino acid turnover and oxidation in chronically catheterized awake male Sprague-Dawley rats using stochastic modeling and a primed continuous infusion of L-[1-14C] leucine. Whole body protein turnover was accelerated by acidosis as reflected in a 70% increase in proteolysis and a 55% increase in protein synthesis. Amino acid oxidation was increased 145% in rats with chronic metabolic acidosis relative to control rats receiving diets identical in protein and calories based on a reciprocal pool model and plasma α-ketoisocaproate specific radioactivity. These changes were accompanied by a 104% increase in liver branched-chain ketoacid dehydrogenase (BCKAD) activity in rats with acidosis, similar to previously documented increases in skeletal muscle BCKAD activity caused by acidosis. In contrast, kidney BCKAD activity was decreased 38% by acidosis, illustrating the tissue-specificity of the changes that were present. We conclude that chronic metabolic acidosis accelerates whole body protein turnover and affects the reincorporation of amino acid into body proteins by accelerating amino acid oxidation.