Synthesis and biological characterisation of [3H]BBL454, a new CCK2 selective radiolabelled agonist displaying original pharmacological properties

[3H]BBL454, a new CCK2 selective tritiated agonist was prepared via the reductive tritiation of a 5-aminopentyn-1-yl moiety introduced on the N-terminal end of a pentapeptide derivative of cholecystokinin. The binding properties of this labelled compound were determined on CHO cells transfected with the rat CCK2 receptor. [3H]BBL454 is able to discriminate two affinity states of the CCK2 receptor a supplementary indication of its validity for further exploring the heterogeneity of this receptor.