LEUCINE TURNOVER IN PATS W/ NEPHROTIC SYN: POSSIBLE BODY PROTEIN CONSERVATION

肾病综合征 PATS 中亮氨酸的转化：可能的身体蛋白质保护

• 批准号: 6118555
• 负责人: VICTORIA S LIM
• 金额: $ 0.32万
• 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/6118555
• 关键词: biomedical resource; female; human subject; male; proteins; spectrometry; urinary tract

Whole body leucine flux was measured in eight patients with nephrotic syndrome and in five normal subjects by primed-constant intravenous infusion of L-[l-13C]leucine. Plasma enrichment of 13C leucine and 13CKIC were measured by gas chromatography/mass spectrometry and exhaled 13CO2 by isotope ratio mass spectrometry. All parameters of leucine flux, including the rates of leucine oxidation, leucine release from protein degradation and, to a lesser extent, leucine incorporation into protein, were reduced in the nephrotic patients. The values (means (SD, umol/kg/hr) of the different parameters in the nephrotic patients and the controls were: Leucine derived from protein degradation, 99(6 and 117; leucine oxidation rate 15(7 and 22(3, (p=0.04) the rate of leucine incorporation into whole body protein, 8484+10 and 95+6, (p=0.04), and net leucine balance which is the difference between the rates of protein synthesis and degradation was -15+7 and -22+3, (p=0.04). T he negative values are due to the fact that measurements were made after a 12 hr fast. Protein turnover rate, calculated from leucine flux, were 3.9+0.4 and 4.7+0.3 g/kg/day in the nephrotic and the control groups (p=0.007). Nitrogen balance, measured only in the nephrotic patients, showed a mean positive balance of 0.5 g/day. For days prior to study the patients ingested a controlled diet consisting of 0.84 g protein/kg/d and 33.3(9 Kcal/kg/day. Thus, at this level of protein/energy intake, nephrotic patients maintained nitrogen balance perhaps because of a metabolic adaptation that resulted in a down regulation of protein degradation and amino acid oxidation rates.

测量了八名患有以下疾病的患者的全身亮氨酸通量 肾病综合征和五名正常受试者的启动常数 静脉输注L-[l-13C]亮氨酸。 13C 的血浆富集 通过气相色谱/质量测定亮氨酸和 13CKIC 通过同位素比质谱法测定呼出的 13CO2。 亮氨酸通量的所有参数，包括亮氨酸的速率 氧化，蛋白质降解释放亮氨酸，并且减少 亮氨酸掺入蛋白质的程度在 肾病患者。 的值（平均值（SD，umol/kg/hr）） 肾病患者和对照组的不同参数是： 源自蛋白质降解的亮氨酸，99（6 和 117；亮氨酸 氧化速率 15(7 和 22(3, (p=0.04)) 亮氨酸速率 掺入全身蛋白质，8484+10 和 95+6，(p=0.04)，以及 净亮氨酸平衡，这是比率之间的差异 蛋白质合成和降解为-15+7和-22+3，(p=0.04)。 这 负值是由于测量是在之后进行的 12小时禁食。 蛋白质周转率，根据亮氨酸通量计算， 肾病组和对照组分别为 3.9+0.4 和 4.7+0.3 g/kg/天 组（p=0.007）。 氮平衡，仅在肾病中测量 患者的平均正平衡为 0.5 克/天。 前几天 研究患者摄入的受控饮食包含 0.84 克 蛋白质/kg/天和33.3（9 Kcal/kg/天。因此，在这个水平 蛋白质/能量摄入，肾病患者维持氮平衡 也许是因为代谢适应导致了下降 蛋白质降解和氨基酸氧化速率的调节。