Deferrari G, Garibotto G, Robaudo C, Canepa A, Bagnasco S, Tizianello A
Clin Sci (Lond). 1985 Aug;69(2):143-51. doi: 10.1042/cs0690143.
Leg metabolism of amino acids and ammonia in the postabsorptive state was evaluated in 10 patients with chronic renal failure (CRF) and in 10 patients with normal renal function (controls) by measuring the arterial-femoral venous (A-FV) differences for free amino acids and ammonia. Total amino acid release from the leg and alanine and glutamine release, which accounts for the greatest amount of the total amino acid release, are similar in patients and controls. Total amino acid uptake from the arterial blood and glutamate uptake, which is the amino acid extracted at the highest rate, are comparable in both groups. Taken together these data, in addition to the similarity of A-FV differences for proteolytic markers, namely tyrosine, phenylalanine and histidine, suggest that protein breakdown in peripheral tissues is not increased in patients with CRF. In CRF selective metabolic abnormalities for some amino acids are evident. Whilst only the A-FV differences for valine, leucine and isoleucine are decreased, additional alterations are observed by relating the A-FV difference for each amino acid to that of proteolytic markers. Such a procedure demonstrates that in CRF histidine release relative to that of proteolytic markers is reduced, whereas proline and arginine release is increased. In CRF the reduced release of some amino acids, mainly branched-chain amino acids, by the leg probably affects the pattern of circulating amino acids. Finally, both in patients and in controls a significant uptake of ammonia is observed; the ammonia uptake is related to arterial levels of this metabolite, confirming the role of peripheral tissues in removing ammonia from circulation.
通过测量游离氨基酸和氨的动脉 - 股静脉（A - FV）差值，对10例慢性肾衰竭（CRF）患者和10例肾功能正常患者（对照组）在吸收后状态下腿部氨基酸和氨的代谢进行了评估。患者和对照组腿部总的氨基酸释放量以及占总氨基酸释放量最大部分的丙氨酸和谷氨酰胺释放量相似。两组中动脉血总的氨基酸摄取量以及摄取速率最高的氨基酸谷氨酸的摄取量相当。综合这些数据，除了蛋白水解标记物（即酪氨酸、苯丙氨酸和组氨酸）的A - FV差值相似外，提示CRF患者外周组织中的蛋白质分解并未增加。在CRF患者中，某些氨基酸存在明显的选择性代谢异常。虽然只有缬氨酸、亮氨酸和异亮氨酸的A - FV差值降低，但通过将每种氨基酸的A - FV差值与蛋白水解标记物的差值相关联，还观察到了其他变化。这样的操作表明，在CRF患者中，相对于蛋白水解标记物，组氨酸的释放减少，而脯氨酸和精氨酸的释放增加。在CRF患者中，腿部某些氨基酸（主要是支链氨基酸）释放减少可能会影响循环氨基酸的模式。最后，在患者和对照组中均观察到显著的氨摄取；氨摄取与该代谢产物的动脉水平相关，证实了外周组织在从循环中清除氨方面的作用。
