Böhler J, Glöer D, Reetze-Bonorden P, Keller E, Schollmeyer P J
Department of Nephrology, University of Freiburg, Germany.
Clin Nephrol. 1993 Mar;39(3):145-50.
The concept of renal functional reserve (RFR) is used in the evaluation of renal function in health and disease. RFR is defined as the difference between glomerular filtration rate (GFR) at rest and the maximum GFR for example under stimulation by an amino acid infusion or a protein rich meal. GFR decreases normally with age by about 1 ml/min per year. The purpose of this study was to establish the effect of the GFR decrease with age on absolute and relative values of RFR. We investigated 12 hospitalized patients 60 to 85 years of age (mean 74 +/- 2.0 SEM) recovering from nonrenal disease. On two consecutive days, inulin and paraaminohippuric acid (PAH) clearance was performed over a period of 4 hours. On day A patients received 1 liter of a 5% glucose solution i.v. On day B an equal volume of an amino acid solution (2 mg/kg/min) was given. In these elderly patients baseline GFR without stimulation measured 73.2 +/- 7.9 ml/min per 1.73 m2 and stimulated GFR was 99.1 +/- 8.5 ml/min, a 35.3% increase (p < 0.025). Thus, renal functional reserve measured 25.9 +/- 8.7 ml/min. PAH clearance increased from 329.0 +/- 41.9 ml/min per 1.73 m2 to 438.8 +/- 50.3 ml/min (p < 0.025). These data confirm that baseline GFR is lower in the elderly compared to young adults. However, renal functional reserve is well maintained in elderly human subjects. This suggests that glomerulosclerosis of aging may not be the only explanation for the low baseline GFR in the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)
肾功能储备（RFR）的概念用于评估健康和疾病状态下的肾功能。RFR定义为静息状态下的肾小球滤过率（GFR）与最大GFR之间的差值，例如在输注氨基酸或进食富含蛋白质的餐食刺激下的最大GFR。GFR通常随年龄增长每年下降约1 ml/min。本研究的目的是确定GFR随年龄下降对RFR绝对值和相对值的影响。我们调查了12名60至85岁（平均74±2.0 SEM）因非肾脏疾病住院康复的患者。在连续两天的时间里，进行了为期4小时的菊粉和对氨基马尿酸（PAH）清除率测定。在A日，患者静脉输注1升5%葡萄糖溶液。在B日，给予等量的氨基酸溶液（2 mg/kg/min）。在这些老年患者中，未刺激时的基线GFR为每1.73 m² 73.2±7.9 ml/min，刺激后的GFR为99.1±8.5 ml/min，增加了35.3%（p<0.025）。因此，肾功能储备为25.9±8.7 ml/min。PAH清除率从每1.73 m² 329.0±41.9 ml/min增加到438.8±50.3 ml/min（p<0.025）。这些数据证实，与年轻人相比，老年人的基线GFR较低。然而，老年人体的肾功能储备保持良好。这表明衰老引起的肾小球硬化可能不是老年人基线GFR低的唯一原因。（摘要截断于250字）
