A Highly Specific and Sensitive Radioimmunoassay of Caerulein,An Analogue of Cholecystokinin-8 |
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Authors: | Goro Kominami Shusuke Mori Keiko Sagawa Ken'Ichi Igano Ken Inouye Masao Kono |
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Institution: | 1. Shionogi Research Laboratories, Shionogi &2. Co., Ltd. , Fukushima-ku, Osaka, 553, Japan |
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Abstract: | Abstract A highly specific and sensitive competitive radioimmunoassay was developed for caerulein (CLN), an analogue of cholecystokinin-8 (CCK-8), in plasma and brain. Antiserum was produced in rabbit by immunization with Nδ-CLN-(1-6)]-ornithine amide conjugated with bovine serum albumin by the glutaraldehyde method. Nα-CLN-(1-6)]-lysine amide was labelled with 125I-Bolton & Hunter reagent and used as a labelled antigen after purification by high-performance liquid chromerography. This assay was highly specific for CLN, and cross reactivities for other related peptides, CCK-4, CCK-8, gastrin-I, and gastrin-(14–17), were not observed (<0.01%). The limits of determination in biological specimens after CLN administration were 11 pg/ml in human plasma and rat plasma and 80 pg/g in rat brain. This study showed that the slight structure difference between hapten and 125I-labelled antigen is important to the assay performance. |
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Keywords: | Caerulein Radioimmunoassay 125I-Label Synthetic peptides Antibody specificity |
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