The degree of NCR selectivity was variable with III-BTD displaying the poorest selectivity. Data for Ro65-6570 are shown in Fig. The effects of Nphe 1 and J-113397 on NC response are from Hashimoto et al. We have demonstrated that a novel NCR ligand, Ro65-6570, acts as a full agonist in CHO hNCR cells. This is in line with the initial report of Wichmann et al.
All compounds behave as competitive antagonists.
Careful comparison of the binding and functional data for the ligands used in this study reveals a discrepancy. In general, receptor binding affinities for antagonists should predict their potencies in functional assays. In contrast, the high level of receptor expression suggests the presence of a large receptor reserve and hence agonists induce the maximal effect by occupying just a small fraction of the available receptors, i.e., for agonists the occupancy curves are shifted to the right compared to the response curves.