Yasui T, Alhenc-Gelas F, Corvol P, Menard J
J Lab Clin Med. 1984 Nov;104(5):741-51.
Angiotensin I-converting enzyme (ACE) is present in human amniotic fluid. We characterized the enzyme by both its antigenic and enzymatic properties. Using a specific direct radioimmunoassay, ACE was quantified and characterized in each of the 19 samples tested. Mean level was 136 +/- 83 ng/ml. Amniotic ACE completely crossreacted, like that in plasma and kidney, with antibodies raised against the lung enzyme. ACE activity in amniotic fluid averaged 8.7 +/- 5.6 microU/ml using Hip-His-Leu as substrate and was significantly correlated with ACE antigen levels. ACE was not associated with the cells or the free intracellular organelles in amniotic fluid, and the enzyme was present in soluble form. Angiotensinase activity and high levels of kininase activity were found in amniotic fluid. Inhibition studies with captopril and anti-human ACE antibodies suggest that angiotensinases and kininases other than ACE were also present. Because renin, mostly in inactive form, and angiotensinogen were also found in these amniotic fluids, it appears that a complete, although not fully activated, renin angiotensin system is present in amniotic fluid and fetal membranes during pregnancy.
血管紧张素I转换酶（ACE）存在于人类羊水当中。我们通过其抗原特性和酶活性对该酶进行了表征。使用特异性直接放射免疫分析法，对所检测的19份样本中的每一份进行了ACE的定量和表征。平均水平为136±83 ng/ml。羊水ACE与针对肺酶产生的抗体完全交叉反应，就如同血浆和肾脏中的ACE一样。以Hip-His-Leu为底物时，羊水ACE活性平均为8.7±5.6 μU/ml，且与ACE抗原水平显著相关。ACE与羊水中的细胞或游离细胞内细胞器无关，该酶以可溶形式存在。羊水中发现了血管紧张素酶活性和高水平的激肽酶活性。用卡托普利和抗人ACE抗体进行的抑制研究表明，除ACE外还存在其他血管紧张素酶和激肽酶。由于在这些羊水中也发现了大多处于无活性形式的肾素和血管紧张素原，因此看来在孕期羊水和胎膜中存在一个完整的、尽管未完全激活的肾素血管紧张素系统。
