Schalm S W, van Berge-Henegouwen G P, Hofmann A F, Cowen A E, Turcotte J
Gastroenterology. 1977 Aug;73(2):285-90.
A rapid, sensitive, precise radioimmunoassay for conjugates of chenodeoxycholic (chenic) acid has been developed and validated. Immunogen was prepared with chenylglycine couples to bovine serum albumin, emulsified in Freund's complete adjuvant, and injected intracutaneously in rabbits. Antibodies of moderate titer (used at 1:7500 final dilution) were obtained. Tracer of high specific activity was prepared by reductive tritiation of delta11-chenylglycine. The binding step required 1 hr at room temperature; separation of bound tracer was achieved by addition of ammonium sulfate. The limit of sensitivity of the assay was about 20 nmoles per liter, and the lower limit of the working range was 0.4 mumole per liter. The assay was validated by measuring levels in samples of fasting state serum to which known amounts of chenylglycine had been added; the assay was also validated by means of gas-liquid chromatography on sera from jaundiced patients. The median fasting state serum level in 56 Caucasians and blacks was 0.9 mumole per liter (upper limit of normal (95% confidence) being 2.3), which is in the same range as that reported by others using gas-liquid chromatography. A 5- to 10-fold increase in levels of chenyl conjugates was observed 1 hr after the ingestion of a liquid meal in healthy persons.
已开发并验证了一种用于鹅去氧胆酸结合物的快速、灵敏、精确的放射免疫分析方法。免疫原是通过将苯甘氨酸与牛血清白蛋白偶联制备的，在弗氏完全佐剂中乳化后，皮内注射到兔子体内。获得了滴度适中的抗体（最终稀释度为1:7500）。通过对δ11 - 苯甘氨酸进行还原氚标记制备了高比活度的示踪剂。结合步骤在室温下需要1小时；通过加入硫酸铵实现结合示踪剂的分离。该分析方法的灵敏度极限约为每升20纳摩尔，工作范围的下限为每升0.4微摩尔。通过测量添加了已知量苯甘氨酸的空腹状态血清样本中的水平来验证该分析方法；还通过对黄疸患者血清进行气液色谱分析来验证该方法。56名白种人和黑人空腹状态血清水平的中位数为每升0.9微摩尔（正常上限（95%置信区间）为2.3），这与其他人使用气液色谱法报告的范围相同。在健康人摄入流食1小时后，观察到苯结合物水平增加了5至10倍。
