Kinoshita H, Fujimoto S, Kitamura K, Matsuura Y, Uezono S, Hisanaga S, Eto T
First Department of Internal Medicine, Miyazaki Medical College, Miyazaki, Japan.
Nephron. 2000 Nov;86(3):333-8. doi: 10.1159/000045789.
Adrenomedullin (AM) is a potent vasodilative and natriuretic peptide that is processed from its precursor as the intermediate form, AM-glycine-COOH (iAM). Subsequently, iAM is converted to the biologically active mature form, AM(1-52)-CONH(2) (mAM), by enzymatic amidation. Using immunoradiometric assays that recognize total AM (tAM) and only mAM, we determined the plasma and urinary levels of mAM and iAM in patients with chronic glomerulonephritis (CGN). The plasma mAM concentration was significantly higher in the patients than in the controls (1.8 +/- 0.1 vs. 1.3 +/- 0.1 fmol/ml, p < 0.01), whereas the plasma iAM concentration of the CGN patients did not significantly differ from that of the controls (9.4 +/- 0.5 vs. 8.9 +/- 0.5 fmol/ml). Levels of urinary mAM excretion in the patients did not statistically differ from those of the controls (1. 6 +/- 0.4 vs. 2.0 +/- 0.3 fmol/mg creatinine), whereas urinary iAM excretion was significantly lower in the CGN patients (3.7 +/- 0.7 vs. 5.6 +/- 0.8 fmol/mg creatinine, p < 0.05). Urinary excretion levels of mAM significantly correlated with those of sodium (r = 0. 47, p < 0.05), whereas those of iAM did not. In conclusion, the plasma ratio of mAM to iAM is augmented in CGN patients, and mAM appears to be involved in the regulation of sodium. Therefore, determination of the mAM in addition to the tAM concentration is essential in CGN patients.
肾上腺髓质素（AM）是一种强效的血管舒张和利钠肽，它以前体形式作为中间产物AM-甘氨酸-COOH（iAM）进行加工。随后，iAM通过酶促酰胺化转化为具有生物活性的成熟形式AM(1-52)-CONH(2)（mAM）。我们使用能识别总AM（tAM）和仅mAM的免疫放射分析方法，测定了慢性肾小球肾炎（CGN）患者血浆和尿液中mAM和iAM的水平。患者血浆mAM浓度显著高于对照组（1.8±0.1对1.3±0.1 fmol/ml，p<0.01），而CGN患者的血浆iAM浓度与对照组无显著差异（9.4±0.5对8.9±0.5 fmol/ml）。患者尿液中mAM排泄水平与对照组无统计学差异（1.6±0.4对2.0±0.3 fmol/mg肌酐），而CGN患者尿液中iAM排泄显著降低（3.7±0.7对5.6±0.8 fmol/mg肌酐，p<0.05）。尿液中mAM排泄水平与钠排泄水平显著相关（r = 0.47，p<0.05），而iAM与钠排泄水平无相关性。总之，CGN患者血浆中mAM与iAM的比例增加，且mAM似乎参与钠的调节。因此，对于CGN患者，除了测定tAM浓度外，测定mAM也至关重要。
