Barrett J D, Eggena P, Sowers J R, Sambhi M P
Am J Physiol. 1982 Sep;243(3):E206-12. doi: 10.1152/ajpendo.1982.243.3.E206.
Little information is available concerning inactive renin in rat plasma. A renin assay method has now been developed for measurement of active and inactive renin in approximately 0.1 ml rat plasma. Trypsin treatment of plasma (5.0 mg trypsin/ml plasma for 5 min at 0 degrees C) to maximally increase the rate of angiotensin I generation did not alter the Km or pH optimum of the renin reaction. Utilizing trypsin, 79 +/- 6% of the total renin (active + inactive) in normal rat plasma is in the inactive form. In vivo stimulation of renin by restraint stress induces a reciprocal change in active and inactive plasma plasma renin, and exposure of animals to ether elevates active and total renin, whereas inactive renin shows a small but nonstatistical decline. Although a parallel disappearance of active and inactive renin is observed after bilateral nephrectomy of the pentobarbital-anesthetized animal, complete occlusion of the renal arteries and veins after ether-induced renin stimulation results in a significant increase of inactive renin. This suggests that possibility of formation of inactive renin from the active enzyme in high renin states. These studies indicate that the balance of active and trypsin-activable renins in rat plasma may be dependent or not only the method but also the degree of in vivo renin stimulation.
关于大鼠血浆中无活性肾素的信息较少。现已开发出一种肾素测定方法，用于测量约0.1 ml大鼠血浆中的活性和无活性肾素。用胰蛋白酶处理血浆（在0℃下，5.0 mg胰蛋白酶/ml血浆处理5分钟）以最大程度提高血管紧张素I的生成速率，并未改变肾素反应的米氏常数（Km）或最适pH值。利用胰蛋白酶，正常大鼠血浆中总肾素（活性+无活性）的79±6%呈无活性形式。束缚应激在体内刺激肾素会导致活性和无活性血浆肾素发生相反变化，动物暴露于乙醚中会使活性肾素和总肾素升高，而无活性肾素则有小幅但无统计学意义的下降。虽然在戊巴比妥麻醉的动物双侧肾切除后观察到活性和无活性肾素平行消失，但在乙醚诱导肾素刺激后完全阻断肾动静脉会导致无活性肾素显著增加。这表明在高肾素状态下，可能由活性酶形成无活性肾素。这些研究表明，大鼠血浆中活性肾素和可被胰蛋白酶激活的肾素之间的平衡可能不仅取决于方法，还取决于体内肾素刺激的程度。
