Cowen A E, Korman M G, Hofmann A F, Turcotte J, Carter J A
J Lipid Res. 1977 Nov;18(6):698-703.
A sensitive, rapid radioimmunoassay for sulfated species of lithocholic acid (sulfolithocholyglycine, sulfolithocholyltaurine, and sulfolithocholic acid) was developed and used to measure the total concentration of sulfated lithocholates in serum from healthy human subjects. Sulfolithocholylglycine was conjugated to bovine serum albumin by a carbodiimide procedure, and the reaction product, emulsified in Freund's adjuvant, was injected into rabbits. The antiserum obtained was capable to binding 40% of [3H]sulfolithocholylglycine at 1:1000 dilution. The assay featured a 2-hr binding step at 42 degrees C followed by precipitation of bound tracer with polyethylene glycol at 4 degrees C. The assay can be used with 0.1 ml of serum and was reproducible. The antibody had little affinity for the 3-sulfate of cholic or chenodeoxycholic acid, a number of steroid sulfates, or unsulfated bile acids. In 50 healthy subjects, mean (+/-SE) fasting-state serum levels of immunoreactive sulfated lithocholyl conjugates (+sulfated lithocholate) was 1.6 +/- 0.1 micrometer; based on results with a separate radioimmunoassay for unsulfated lithocholyl conjugates, most of the lithocholate in serum in healthy man is present in sulfated form.
开发了一种灵敏、快速的用于检测石胆酸硫酸化产物（硫酸石胆酰甘氨酸、硫酸石胆酰牛磺酸和硫酸石胆酸）的放射免疫分析方法，并用于测定健康人体血清中硫酸化石胆酸盐的总浓度。通过碳二亚胺法将硫酸石胆酰甘氨酸与牛血清白蛋白偶联，将反应产物在弗氏佐剂中乳化后注射到兔子体内。获得的抗血清在1:1000稀释时能够结合40%的[3H]硫酸石胆酰甘氨酸。该分析方法的特点是在42℃下进行2小时的结合步骤，然后在4℃下用聚乙二醇沉淀结合的示踪剂。该分析方法可用于0.1ml血清，且具有可重复性。该抗体对胆酸或鹅去氧胆酸的3-硫酸盐、多种类固醇硫酸盐或未硫酸化的胆汁酸几乎没有亲和力。在50名健康受试者中，免疫反应性硫酸化石胆酰偶联物（+硫酸化石胆酸盐）的空腹状态血清平均（±标准误）水平为1.6±0.1微摩尔；根据单独用于未硫酸化石胆酰偶联物的放射免疫分析结果，健康男性血清中的大多数石胆酸盐以硫酸化形式存在。
