Hermann K, Ganten D, Unger T, Bayer C, Lang R E
Department of Pharmacology, University of Heidelberg, F.R.G.
Clin Chem. 1988 Jun;34(6):1046-51.
We report a method for the extraction of angiotensin peptides from plasma with a mixture of acetone, 1 mol/L HCl, and water (40/1/5 by vol). The method is highly reproducible for the measurement of angiotensin I and angiotensin II in small sample volumes, with analytical recoveries of about 80% for both peptides. We investigated the influence of sample handling and found a standard procedure for blood collection, plasma preparation, and extraction was essential. The method was used to measure angiotensin I and II in rat and human plasma. In rat plasma, the mean (+/- SEM) concentrations of angiotensin I and angiotensin II were determined to be 67 (+/- 8) and 14 (+/- 1) pmol/L (n = 10), respectively. Neither angiotensin I nor angiotensin II was detectable 24 h after bilateral nephrectomy. Acute oral administration of the converting-enzyme inhibitor ramipril caused a significant increase of angiotensin I from 85 (+/- 6) to 257 (+/- 33) pmol/L (n = 10; P less than 0.001) and a significant decrease of angiotensin II from 12 (+/- 1) to 7 (+/- 0.4) pmol/L in rat plasma (n = 9; P less than 0.001). In human plasma, angiotensin I and angiotensin II values of 21 (+/- 1) and 6.6 (+/- 0.5) pmol/L (n = 10) were found. A single oral dose of the diuretic furosemide increased angiotensin I significantly from 21 (+/- 1) to 32 (+/- 1.7) pmol/L (n = 5); P less than 0.001), whereas angiotensin II remained unchanged, 6.6 (+/- 0.5) vs 6.4 (+/- 0.4) pmol/L (n = 5). Extracted peptides could be identified as [IIe5]-angiotensin I and [IIe5]-angiotensin II by HPLC in combination with specific radioimmunoassays for angiotensin I and angiotensin II.
我们报道了一种用丙酮、1mol/L盐酸和水（体积比为40/1/5）的混合物从血浆中提取血管紧张素肽的方法。该方法对于小样本量中血管紧张素I和血管紧张素II的测量具有高度可重复性，两种肽的分析回收率约为80%。我们研究了样本处理的影响，发现血液采集、血浆制备和提取的标准程序至关重要。该方法用于测量大鼠和人血浆中的血管紧张素I和II。在大鼠血浆中，血管紧张素I和血管紧张素II的平均（±SEM）浓度分别测定为67（±8）和14（±1）pmol/L（n = 10）。双侧肾切除术后24小时，血管紧张素I和血管紧张素II均未检测到。急性口服转化酶抑制剂雷米普利导致大鼠血浆中血管紧张素I从85（±6）显著增加至257（±33）pmol/L（n = 10；P<0.001），血管紧张素II从12（±1）显著降低至7（±0.4）pmol/L（n = 9；P<0.001）。在人血浆中，发现血管紧张素I和血管紧张素II的值分别为21（±1）和6.6（±0.5）pmol/L（n = 10）。单次口服利尿剂呋塞米使血管紧张素I从21（±1）显著增加至32（±1.7）pmol/L（n = 5；P<0.001），而血管紧张素II保持不变，分别为6.6（±0.5）和6.4（±0.4）pmol/L（n = 5）。通过高效液相色谱结合血管紧张素I和血管紧张素II的特异性放射免疫分析，提取的肽可被鉴定为[Ile5]-血管紧张素I和[Ile5]-血管紧张素II。
