Ohgo S, Takemura J, Oki Y, Nishizono F, Ishikawa E, Yoshimi T, Yamamura T, Seino Y, Matsukura S
Department of Internal Medicine, Miyazaki Medical College, Japan.
Clin Chem. 1988 Aug;34(8):1579-84.
A sensitive and specific radioimmunoassay for cholecystokinin (CCK) has been developed. Synthetic unsulfated carboxy-terminal fragment, CCK-8, was radioiodinated by the conventional Chloramine-T method. Antibodies were raised against sulfated CCK-8 covalently coupled to bovine thyroglobulin via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. By purification, highly immunoreactive 125I-labeled CCK-8 was obtained. The antiserum was highly avid, and plasma could be assayed directly. The detection limit of the assay was 5 pmol of sulfated CCK-8 per liter. The assay measured fragments CCK-8, CCK-33, and CCK-39 with equimolar potency. CCK-4, gastrin, and vasoactive intestinal polypeptide were not detected, even at higher concentrations. The concentration of CCK, as the sum of these CCK peptides, in plasma during fasting was low (10.5 +/- 2.1 pmol/L, mean +/- SEM) but still detectable in all normal subjects examined (range, 6.4-20.1 pmol/L). After ingestion of a test meal, CCK in plasma increased rapidly, peaking at 41.3 (SEM 5.7) pmol/L at 40 min and remaining high for 3 h after the meal. This supports the concept that CCK has important roles in digestion and absorption.
已开发出一种用于胆囊收缩素（CCK）的灵敏且特异的放射免疫分析方法。通过传统的氯胺-T法对合成的无硫酸化羧基末端片段CCK-8进行放射性碘化。针对通过1-乙基-3-（3-二甲基氨基丙基）碳二亚胺与牛甲状腺球蛋白共价偶联的硫酸化CCK-8产生抗体。通过纯化，获得了高免疫活性的125I标记的CCK-8。抗血清具有高亲和力，血浆可直接进行检测。该分析方法的检测限为每升5皮摩尔硫酸化CCK-8。该分析方法以等摩尔效力测定片段CCK-8、CCK-33和CCK-39。即使在较高浓度下，也未检测到CCK-4、胃泌素和血管活性肠肽。空腹时血浆中这些CCK肽总和形式的CCK浓度较低（10.5±2.1皮摩尔/升，平均值±标准误），但在所检查的所有正常受试者中仍可检测到（范围为6.4 - 20.1皮摩尔/升）。摄入试验餐后，血浆中的CCK迅速增加，在40分钟时达到峰值41.3（标准误5.7）皮摩尔/升，并在餐后3小时内保持在较高水平。这支持了CCK在消化和吸收中具有重要作用的观点。
