UREMIA, ACIDOSIS & DIALYSIS ON PROTEIN METABOLISM: LONGITUDINAL LEUCINE KINETICS

尿毒症、酸中毒

• 批准号: 6118556
• 负责人: VICTORIA S LIM
• 金额: $ 0.16万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 1999-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6118556
• 关键词: biomedical resource; female; human subject; male; prosthesis; proteins; spectrometry; urinary tract

Uremia and dialysis are viewed as catabolic processes resulting in malnutrition in chronic renal failure (CRF) patients. To sort out the effects of uremia, acidosis and dialysis on protein metabolism, we measured leucine flux in CRF patients before and after initiation of maintenance dialysis. Whole body leucine flux was measured by primed-constant infusion of L[1-13C]leucine in 9 CRF patients longitudinally; twice before and once after initiation of maintenance dialysis [D]. Before dialysis, one leucine flux was measured when the patients were acidotic [A], and the other, when acidosis was corrected with NaHCO3[NA]. Five normal subjects underwent one single leucine flux measurement to serve as control [N]. Both patients and normal subjects consumed a constant diet for 6 days and leucine flux was measured on the 7th day 12 hr. post-absorption. Diet for the CRF patients was identical during the three periods. Plasma L[1-13C] leucine and L[1-13C]KIC were measured by gas c hromatography/mass spectrometry and expired 13CO2 by isotope ratio spectrometry. Leucine kinetics were calculated using standard equations. Plasma CO2 were 19,26 and 31 mmol/L in A, NA and D periods, respectively. All kinetic results ((mol/kg/hr) are presented as means (SD in the order of A, NA, D and N, and CRF values that are statistically different from N are identified [*]. The amount of leucine release from endogenous protein breakdown [Ra or Q] were 101(12*, 95(9*, 113(22 and 117(6. Leucine oxidation [C], quantity of leucine irreversibly oxidized to CO2, were 16.5(5.4, 9.7(3.7*, 12.3(3.0* and 23.2(3.1. Leucine protein incorporation [S] were 85(10, 85(8, 101(19 and 94(6. The S of 101 in CRF patients at period D was statistically higher than those during A and NA periods. These data indicate that when acidosis was corrected, CRF patients adapted to lower protein intake by reducing amino acid oxidation and protein degradation, and maintained protein synthesis at normal level . Metabolic acidosis impaired the down regulation of amino acid oxidation. Maintenance dialysis treatment longitudinally restored protein flux to normal and increased protein synthesis. The general notion that uremia and dialysis are protein catabolic are not supported by this work.

尿毒症和透析被视为分解代谢过程，导致 慢性肾衰竭（CRF）患者营养不良。 为了整理出 尿毒症、酸中毒和透析对蛋白质代谢的影响，我们 测量 CRF 患者开始治疗前后的亮氨酸通量 维持透析。 全身亮氨酸通量通过以下方式测量 9 例 CRF 患者持续灌注 L[1-13C]亮氨酸 纵向；维护开始前两次和维护开始后各一次 透析[D]. 透析前，在以下情况下测量一次亮氨酸通量： 患者酸中毒[A]，另一例，当酸中毒得到纠正时 与 NaHCO3[NA]。 五名正常受试者接受了一次单一亮氨酸治疗 通量测量作为控制[N]。 无论是患者还是正常人 受试者连续 6 天保持恒定饮食，亮氨酸通量为 第7天12小时测量。 吸收后。 CRF的饮食 三个时期的患者是相同的。 血浆L[1-13C] 通过气相色谱/质谱法测量亮氨酸和 L[1-13C]KIC 通过同位素比光谱法测定呼出的 13CO2。 亮氨酸 使用标准方程计算动力学。 血浆 CO2 为 A、NA 和 D 时段分别为 19,26 和 31 mmol/L。 全动能 结果（（mol/kg/hr）以平均值（SD 按 A、NA、 D 和 N，以及与 N 有统计差异的 CRF 值是 已识别[*]。 内源蛋白质释放亮氨酸的量 分解[Ra 或 Q] 为 101(12*, 95(9*, 113(22 和 117(6. 亮氨酸 氧化 [C]，亮氨酸不可逆氧化成 CO2 的量， 16.5(5.4, 9.7(3.7*, 12.3(3.0* 和 23.2(3.1. 亮氨酸蛋白 掺入[S]分别为 85(10, 85(8, 101(19 和 94(6)。 101 中的 S D期CRF患者统计学上高于A期患者 和 NA 时段。 这些数据表明，当酸中毒得到纠正后， CRF患者通过减少氨基酸来适应降低蛋白质摄入量 氧化和蛋白质降解，并维持蛋白质合成 正常水平。 代谢性酸中毒损害了 氨基酸氧化。 纵向维持透析治疗 使蛋白质通量恢复正常并增加蛋白质合成。 这 尿毒症和透析是蛋白质分解代谢的一般观念并非如此 这项工作的支持。