title: 125I-(Thr34, Nle37)- CCK31-39 a non oxidizable tracer for the characterization of CCK receptor on pancreatic acini and radio-immunoassay of C-terminal CCK peptides.
abstract: A derivative of the C-terminal nonapeptide of CCK, namely (Thr34, Nle37) - CCK31-39 was radio-iodinated by conjugation with 125I-Bolton-Hunter reagent. The labelled peptide was purified by RP-HPLC on a C-18 column. Validation of the iodinated peptide was performed by measuring its biological integrity and by studying its binding characteristics on pancreatic acini. 125I-(Thr, Nle)-CCK-9 present the same ability to stimulates amylase release than (Thr, Nle)- CCK-9 and CCK-8. Binding of the radio-ligand to CCK receptors is specific, reversible, saturable. Inhibition of the binding by CCK-related peptides correlates well their biological potencies. 125I-(Thr, Nle)-CCK-9 is able to interact with high affinity CCK receptors. Furthermore, 125I-(Thr, Nle)-CCK-9 is recognized by C-terminal CCK directed antibodies. This reliable tracer could be used as a replacement of CCK-8 since it is protected from risks of oxidation.
mesh_terms: D000681:Amylases / Q000378:metabolism; D000818:Animals; D001681:Biological Assay; D002766:Cholecystokinin / Q000031:analogs & derivatives* / Q000276:immunology; D006168:Guinea Pigs; D007467:Iodoproteins; D007700:Kinetics; D010179:Pancreas / Q000378:metabolism; D011863:Radioimmunoassay; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011949:Receptors, Cholecystokinin
chemical_list: D007467:Iodoproteins; D011956:Receptors, Cell Surface; D011949:Receptors, Cholecystokinin; D002766:Cholecystokinin; D000681:Amylases