PROTEIN METABOLISM IN CHRONIC RENAL FAILURE PATIENTS

目的：研究终末期肾病患者的蛋白质代谢， 疾病，我们测量了8例患者的亮氨酸动力学。 研究 进行了两次之前和一次之后（第三阶段）（开始 维持透析治疗。 透析前，一项测量结果为 当病人酸中毒时（第一阶段），另一个在 纠正酸中毒时补充碳酸氢钠（阶段 II）。 阶段I和II的顺序随机化。 受试者接受 在所有三个时期都是相同的恒定饮食。 亮氨酸动力学 在[1- 13 C]亮氨酸的引发恒定输注期间测量， [1- 13 C]KIC或（酮-异己酸盐和呼气CO2富集 是直接决定的。 这些值用于计算亮氨酸 进入血浆亮氨酸池和全身的出现率 亮氨酸库和亮氨酸氧化速率。 前者代表 蛋白质降解率、蛋白质合成率 通过质量平衡方程估计。 亮氨酸氧化程度越高 没有碳酸氢盐补充的比率不是由于较高的VCO 2， 总CO2产生率在三个时期没有不同。 可替代地，可以增加更高比例的内源性产生的CO2。 比在非酸中毒状态下排泄。 最后，这些发现可能 代表在存在下氨基酸氧化的真实的增强 代谢性酸中毒

To study protein metabolism in patients with end-stage renal disease, we measured leucine kinetics in 8 patients. Study was performed twice before and once after (period III)( initiation of maintenance dialysis treatment. Before dialysis, one measurement was done when the patients are acidotic (period I), and the other during sodium bicarbonate supplementation when acidosis was corrected (period II). Sequence of Periods I and II were randomized. Subjects were on identical constant diet during all three periods. Leucine kinetics was measured during primed-constant infusion of [1-13C]leucine, [1-13C]KIC or ( keto-isocaproate and expired breath CO2 enrichment were directly determined. These values were used to calculate leucine appearance rates into the plasma leucine pool and into the total body leucine pool and leucine oxidation rate. The former represents protein degradation rat; protein synthesis rate was indirectly estimated by mass balance equation. The h igher leuc ine oxidation rate without bicarbonate supplementation was not due to higher VCO2 as total CO2 production rate was not different during the three periods. Alternatively, higher proportion of endogenously produced CO2 may be excreted than in the non-acidotic state. Finally, these findings may represent a real enhancement of amino acid oxidation in the presence of metabolic acidosis.