Barrett J D, Eggena P
Vascular Biopharmacology Laboratory, Veterans Administration Medical Center, Sepulveda, California 91343.
Clin Exp Hypertens A. 1987;9(11):1823-41. doi: 10.3109/10641968709158976.
Following trypsin treatment of rat or human plasma, the level of angiotensin I, generated by renin, can be significantly underestimated by radioimmunoassay due to tryptic generation of an angiotensin binding substance. The precursor of the binding substance (void volume-AcA 44 gel) was converted by trypsin to 45K. Analogous to PRC methodology, known concentrations of angiotensin I were added to control and trypsin treated human plasma after the renin incubation step to determine the influence of the binding substance on the measured levels of generated angiotensin I. Using this technique, renin levels in trypsin exposed plasma were approximately two fold higher than when measured by single point conventional assay. If plasma levels of the binding precursor change in response to renin stimulation or suppression, its activation during the trypsin treatment step of the renin assay may explain the relative lack of change of inactive renin observed following numerous in vivo maneuvers.
用胰蛋白酶处理大鼠或人血浆后，由于胰蛋白酶产生一种血管紧张素结合物质，通过放射免疫测定法，肾素产生的血管紧张素I水平可能会被显著低估。结合物质的前体（空体积-AcA 44凝胶）经胰蛋白酶转化为45K。类似于PRC方法，在肾素孵育步骤后，将已知浓度的血管紧张素I添加到对照血浆和经胰蛋白酶处理的人血浆中，以确定结合物质对所测生成的血管紧张素I水平的影响。使用该技术，经胰蛋白酶处理的血浆中的肾素水平比单点常规测定法所测结果高约两倍。如果结合前体的血浆水平因肾素刺激或抑制而发生变化，那么在肾素测定的胰蛋白酶处理步骤中其激活可能解释了在多次体内操作后观察到的无活性肾素相对缺乏变化的现象。
