Radioimmunological Determination of Cholecystokinin in Tissue Extracts

Abstract
A sensitive and precise radioimmunoassay has been developed. Cholecystokinin (CCK) was labeled by the Bolton-Hunter method. The antibody bound CCK8 and CCK33. The binding sites of the antibody are located by the sulfated tyrosil group in position 27 of the CCK molecule. Human duodenum tissue contains larger forms of CCK33 as well as CCK33 and CCK8.