Löfberg E, Wernerman J, Anderstam B, Bergström J
Department of Clinical Science, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden.
Clin Nephrol. 1997 Oct;48(4):230-7.
Earlier studies have shown increased oxidation of the branched-chain amino acids (BCAA), valine, isoleucine and leucine, in experimental acidosis and low levels of valine in the muscle of acidotic HD patients. Using HPLC, free amino acids in plasma and muscle were studied before and after correction of acidosis in 9 HD patients over 6 months by dialysis with a high bicarbonate solution. The predialysis standard bicarbonate concentration in blood increased from 20.6 +/- 1.3 mmol/l (mean +/- SD) before correction of acidosis to 25.9 +/- 1.8 mmol/l after correction. Correction of acidosis resulted in a significant increase in the i.c. concentrations of valine, isoleucine and leucine by 48%, 28% and 32%, as well as for the sum of BCAA and EAA, from a level lower than controls. The intra- and extracellular gradient increased for several amino acids and for the sum of EAA and BCAA, suggesting an increased influx or reduced efflux of amino acids across the cell membrane. Anthropometric data and the levels of S-albumin and transferrin did not change after correction of acidosis. The increases in the i.c. concentrations of BCAA after correction of acidosis suggest that the catabolism of these amino acids had been reduced. The effects of correction of acidosis on the concentrations of essential amino acids could be beneficial since low concentrations in muscle may reduce protein synthesis.
早期研究表明，在实验性酸中毒以及酸中毒的血液透析患者肌肉中缬氨酸水平较低的情况下，支链氨基酸（BCAA）、缬氨酸、异亮氨酸和亮氨酸的氧化增加。使用高效液相色谱法（HPLC），对9名血液透析患者在6个月内用高碳酸氢盐溶液进行透析纠正酸中毒前后的血浆和肌肉中的游离氨基酸进行了研究。酸中毒纠正前血液中的透析前标准碳酸氢盐浓度从20.6±1.3 mmol/L（平均值±标准差）增加到纠正后的25.9±1.8 mmol/L。酸中毒的纠正导致细胞内缬氨酸、异亮氨酸和亮氨酸的浓度显著增加，分别增加了48%、28%和32%，BCAA和必需氨基酸（EAA）的总和也从低于对照组的水平显著增加。几种氨基酸以及EAA和BCAA总和的细胞内外梯度增加，表明氨基酸跨细胞膜的流入增加或流出减少。酸中毒纠正后人体测量数据以及血清白蛋白和转铁蛋白水平没有变化。酸中毒纠正后细胞内BCAA浓度的增加表明这些氨基酸的分解代谢减少。酸中毒的纠正对必需氨基酸浓度的影响可能是有益的，因为肌肉中低浓度的必需氨基酸可能会减少蛋白质合成。
