A new column-chromatographic method is described for the simple and reproducible determination of the concentration of [des-Asp1]angiotensin II (angiotensin III) in rat plasma. 2. The method uses the different abilities of the ion-exchange resins Dowex 1 (X8) and Bio Rex 70 to bind angiotensin II and angiotensin III. Under the conditions used, Bio Rex 70 binds only angiotensin III. Angiotensin II and its hexapeptide metabolite [des-Asp1,des-Arg2]angiotensin II pass the resin with the effluent. Dowex 1 (X8) binds angiotensin II and the hexapeptide metabolite, whereas it does not extract angiotensin III. It does not separate angiotensin II from the hexapeptide. Therefore the sum of both peptides is expressed as angiotensin II-like activity. The ratio of the concentrations, angiotensin II/hexapeptide, was 5:1. 3. In normal rats the plasma concentration of angiotensin III was 20 fmol/ml (SD 15; n = 8), and angiotensin II-like activity was 60 fmol/ml (SD 35; n = 8). 4. The beta-sympathomimetic amine isoprenaline caused a time- and dose-dependent increase in plasma angiotensin III and angiotensin II-like activities. 5. Under the conditions studied angiotensin III contributed approximately 25% to the total amount of angiotensins in plasma.
摘要
本文描述了一种新的柱色谱法，用于简单且可重复地测定大鼠血浆中[去天冬氨酸1]血管紧张素II（血管紧张素III）的浓度。2. 该方法利用离子交换树脂Dowex 1（X8）和Bio Rex 70结合血管紧张素II和血管紧张素III的不同能力。在所使用的条件下，Bio Rex 70仅结合血管紧张素III。血管紧张素II及其六肽代谢物[去天冬氨酸1，去精氨酸2]血管紧张素II随流出液通过树脂。Dowex 1（X8）结合血管紧张素II和六肽代谢物，而不提取血管紧张素III。它不能将血管紧张素II与六肽分离。因此，这两种肽的总和表示为血管紧张素II样活性。血管紧张素II/六肽的浓度比为5:1。3. 在正常大鼠中，血管紧张素III的血浆浓度为20 fmol/ml（标准差15；n = 8），血管紧张素II样活性为60 fmol/ml（标准差35；n = 8）。4. β-拟交感胺异丙肾上腺素引起血浆血管紧张素III和血管紧张素II样活性的时间和剂量依赖性增加。5. 在所研究的条件下，血管紧张素III约占血浆中血管紧张素总量的25%。
