Burhol P G, Rayford P L, Jorde R, Waldum H L, Schulz T B, Thompson J C
Hepatogastroenterology. 1980 Aug;27(4):300-9.
A precise and specific radioimmunoassay method for measuring plasma cholecystokinin (CCK) is described. The present assay system using a stable tracer iodinated by means of a modified Chloramine-T method followed by purification on a Sephadex G-15 and a SP Sephadex C-25 column, as well as careful corrections for non-specific plasma effects, allows measurements of fasting plasma CCK in the low pmol/l range; the significant rise in plasma CCK following duodenal infusion of fat; and the significant diurnal variation of plasma CCK. Apparent immunoreactive meal-stimulated plasma CCK was eluted from a Sephadex G-50 superfine column in four fractions. The first and largest peak probably represents plasma CCK bound to plasma proteins and non-specific plasma effects, the second and smaller peak big CCK with molecular weight between some 5,000 and some 30,000, the shoulders following the second peak ordinary CCK33 and CCK39 variant, and the final, and by far the smallest peak, may possibly represent COOH-terminal tetra- (CCK4) or octapeptides (CCK8) of CCK.
本文描述了一种精确且特异的用于测量血浆胆囊收缩素（CCK）的放射免疫分析方法。目前的分析系统采用经改良氯胺-T法碘化的稳定示踪剂，随后在葡聚糖凝胶G-15和SP葡聚糖凝胶C-25柱上进行纯化，并对非特异性血浆效应进行仔细校正，可测量低皮摩尔/升范围内的空腹血浆CCK；十二指肠输注脂肪后血浆CCK的显著升高；以及血浆CCK明显的昼夜变化。从葡聚糖凝胶G-50超细柱上洗脱的明显的免疫反应性餐后刺激血浆CCK分为四个部分。第一个也是最大的峰可能代表与血浆蛋白结合的血浆CCK和非特异性血浆效应，第二个较小的峰为分子量在约5000至约30000之间的大CCK，第二个峰之后的肩峰为普通CCK33和CCK39变体，最后一个也是迄今为止最小的峰可能代表CCK的羧基末端四肽（CCK4）或八肽（CCK8）。
