Figure 2.

Binding affinity and potency of truncated ACTH peptides in OS3 cells stably transfected with the wild-type hMC2R. Panel A shows that OS3 cells transfected with hMC2R were incubated with ¹²⁵I-ACTH in the presence of the indicated amounts of unlabeled ligands, and total ¹²⁵I-ACTH binding was determined. Panel B shows that the cells were incubated with the indicated amounts of peptides and total cAMP accumulation was determined. (n = 3; see Table 1 for K_i and EC₅₀ values).