Garibotto G, Russo R, Sala M R, Ancarani P, Robaudo C, Sofia A, Deferrari G, Tizianello A
Department of Internal Medicine, University of Genoa, Italy.
Miner Electrolyte Metab. 1992;18(2-5):217-21.
Muscle protein turnover and amino acid (AA) exchange were studied in 4 patients with chronic renal failure (CRF) and in 5 controls in the postabsorptive state by using the forearm perfusion method together with the systemic infusion of 3H-Phe. In CRF patients muscle protein breakdown is increased and is associated with a parallel increase in protein synthesis. Protein breakdown is inversely related to arterial bicarbonate. Net proteolysis is unchanged. The release of total AA, glutamine and alanine is not different from controls, whereas the release of valine and leucine is reduced and serine uptake tends to be decreased. In conclusion, in postabsorptive patients with CRF, well before the uremic stage, an increased protein breakdown associated with metabolic acidosis takes place; net proteolysis is unaffected. Alterations in BCAA metabolism suggest the occurrence of increased BCAA degradation proceeding beyond the transamination step.
采用前臂灌注法并全身输注³H-苯丙氨酸，对4例慢性肾衰竭（CRF）患者和5例处于吸收后状态的对照者的肌肉蛋白质周转和氨基酸（AA）交换进行了研究。在CRF患者中，肌肉蛋白质分解增加，且与蛋白质合成的平行增加相关。蛋白质分解与动脉血碳酸氢盐呈负相关。净蛋白水解未改变。总AA、谷氨酰胺和丙氨酸的释放与对照组无差异，而缬氨酸和亮氨酸的释放减少，丝氨酸摄取趋于减少。总之，在处于吸收后状态的CRF患者中，早在尿毒症阶段之前，就会发生与代谢性酸中毒相关的蛋白质分解增加；净蛋白水解不受影响。支链氨基酸（BCAA）代谢的改变表明，BCAA降解增加发生在转氨基步骤之后。
