The specificity in heterogeneous enzyme immunoassays for cortisol has been investigated. Enzyme labeling of cortisol was accomplished by the N-succinimidyl ester method at an appropriate molar ratio of steroid to enzyme. Three cortisol derivatives possessing different bridges at C-4 were covalently linked to β-galactosidase. The anticortisol antisera used were those elicited in rabbits by immunization with the conjugates of these haptenic derivatives with bovine serum albumin. With the aim of obtaining high sensitivity, enzyme immunoassays were carried out in the bridge heterologous combinations of antiserum and enzyme-labeled cortisol. The specificity of these assay systems was assessed by measuring the amount of cortisol in biological fluids, and by comparison of the results with those of radioimmunoassays. The cross-reactivities were also tested with fifteen kinds of closely related steroids. The assay using the antiserum raised against the 4-(2-carboxyethylthio) cortisol-protein conjugate was found to be relatively specific and applicable to the determination of cortisol in human plasma and urine.
研究了
皮质醇异构酶免疫测定的特异性。通过 N-琥珀
酰亚胺酯法以适当的类
固醇与酶的摩尔比对
皮质醇进行酶标记。三种
皮质醇衍
生物在 C-4 上具有不同的桥,并与
β-半乳糖苷酶共价连接。所使用的抗
皮质醇抗血清是通过用这些合酶衍
生物与
牛血清白蛋白的共轭物对兔子进行免疫而激发的。为了获得高灵敏度,在抗血清和酶标记
皮质醇的桥异源组合中进行了酶免疫测定。通过测量
生物液体中的
皮质醇含量,并将结果与放射免疫测定法的结果进行比较,评估了这些测定系统的特异性。此外,还对 15 种密切相关的类
固醇进行了交叉反应测试。结果发现,使用针对 4-(2-羧基乙
硫基)
皮质醇-蛋白共轭物的抗血清进行的检测具有较高的特异性,适用于测定人体血浆和尿液中的
皮质醇。