Weinberg K S, Douglas W H, MacNamee D R, Lanzillo J J, Fanburg B L
In Vitro. 1982 Apr;18(4):400-6. doi: 10.1007/BF02796341.
Angiotensin I-converting enzyme is responsible for the activation of angiotensin I and the inactivation of bradykinin. It has been localized by immunofluorescence on the endothelium of a variety of tissues and has been considered to be a specific marker for endothelial cells in culture. The present paper demonstrates, by immunofluorescence, the presence of angiotensin I-converting enzyme in monolayer cultures of fibroblasts derived from adult rat lung, bovine calf pulmonary artery, and human foreskin (CF-3 cells). Fluorescent localization of angiotensin I-converting enzyme was observed over the cytoplasm of adult rat lung and bovine calf pulmonary artery fibroblasts and as distinct areas overlying the nuclei of human foreskin fibroblasts. Determination of angiotensin I-converting enzyme activity by fluorimetric assay in parallel studies confirmed the presence of angiotensin I-converting enzyme activity in cultured fibroblasts. Immunofluorescent studies with antibody to Factor VIII demonstrated the presence of Factor VIII on cultured endothelial cells but not on fibroblasts. These results indicate that angiotensin I-converting enzyme is not confined to endothelial cells, and thus may not serve as a specific marker for endothelial cells in culture. Factor VIII may be a more specific marker for these cells.
血管紧张素I转换酶负责血管紧张素I的激活和缓激肽的失活。通过免疫荧光法已将其定位在多种组织的内皮细胞上，并且它被认为是培养的内皮细胞的一种特异性标志物。本文通过免疫荧光法证明，在源自成年大鼠肺、小牛肺动脉和人包皮的成纤维细胞单层培养物（CF - 3细胞）中存在血管紧张素I转换酶。在成年大鼠肺和小牛肺动脉成纤维细胞的细胞质中观察到血管紧张素I转换酶的荧光定位，而在人包皮成纤维细胞核上方则呈现为不同的区域。在平行研究中通过荧光测定法测定血管紧张素I转换酶活性，证实了培养的成纤维细胞中存在血管紧张素I转换酶活性。用抗凝血因子VIII抗体进行的免疫荧光研究表明，培养的内皮细胞上存在凝血因子VIII，而成纤维细胞上则没有。这些结果表明，血管紧张素I转换酶并不局限于内皮细胞，因此可能无法作为培养的内皮细胞的特异性标志物。凝血因子VIII可能是这些细胞更特异的标志物。
