Abstract
Total proteins, angiotensin‐converting enzyme, N‐acetyl‐β‐D‐glucosaminidase, glutamine transaminase K and glutamine synthetase were determined in urine collected overnight (14 h: 6:00 p.m.–8:00 a.m.) from naive male Wistar rats; glutamine transaminase K and glutamine synthetase in the kidney 10 000 g supernatant and p‐aminohippurate uptake in renal cortical slices also were measured. Urinary parameters were related both to urinary creatinine concentration and urinary flow rate; kidney parameters were related to protein concentration (enzymes) or slice/medium (S/M) ratio (p‐aminohippurate uptake). The following reference ranges (1.0 and 99.0 percentiles) were obtained: urine: total urinary proteins (195 samples) 0.03–0.29 g mmol^−1^ creatinine and 0.13–1.77 mg h^−1^; angiotensin‐converting enzyme (115 samples) 8.9–63.7 µmol mmol^−1^ creatinine and 59.4–282.7 nmol h^−1^; glutamine transaminase K (115 samples) 0–1.7 µmol mmol^−1^ creatinine and 0–8.5 nmol h^−1^; N‐acetyl‐β‐D‐glucosaminidase (72 samples) 0.7–5.0 µmol mmol^−1^ creatinine and 4.9–28.4 nmol h^−1^ (naive male rats did not excrete glutamine synthetase); kidney: glutamine transaminase K (36 samples) 14.5–32.8 nmol mg^−1^ protein; glutamine synthetase (22 samples) 13.9–48.6 nmol mg^−1^ protein and p‐aminohippurate (54 samples) 4.77–17.89 S/M. Urinary creatinine (r = −0.780), total urinary proteins (r = −0.521), angiotensin‐converting enzyme (r = −0.650) and N‐acetyl‐β‐D‐glucosaminidase (r = −0.796) but not glutamine transaminase K were well correlated with diuresis. In addition, the same parameters, but not glutamine transaminase K, were well correlated with creatinine (r = 0.604,0.701 and 0.747, respectively). Significant correlation also was observed between urinary indices adjusted to creatinine or urinary flow rate (total urinary proteins: r = 0.813; angiotensin‐converting enzyme: r = 0.677; glutamine transaminase K: r = 0.939; N‐acetyl‐β‐D‐glucosaminidase: r = 0.657). Finally, a low but significant correlation was found between total urinary proteins and angiotensin‐converting enzyme (r = 0.293) and N‐acetyl‐β‐D‐glucosaminidase (r = 0.471). Copyright © 2001 John Wiley & Sons, Ltd.