TABLE 2

cAMP accumulation in CHO-CRF1 cells treated with 1 μM forskolin in response to peptide and nonpeptide ligands

The cAMP response was measured in cells pretreated with pertussis toxin (to minimize inhibition of cAMP accumulation) and treated in the assay with 1 μM forskolin (to amplify constitutive and ligand-stimulated receptor activity). Data have been normalized to basal activity (see legend to Fig. 3). See Supplementary Fig. SIC for peptide ligands. Data are mean ± S.E.M., n = 3 to 14. For nonpeptide ligands, single-factor ANOVA indicated Emax values were significantly different, with the post hoc Newman-Keuls test indicating significant difference between the following groups: NBI 34041, NBI 30775, NBI 35965, NBI 38242 < NBI 77172 < NBI 77173, NBI 77165, and NBI 77178.

Ligand Emax -log EC50 EC50
% basal activity nM
CRF 270 ± 15 11.43 ± 0.09 3.7 pM
Astressin 180 ± 10 8.61 ± 0.26 2.5 nM
Peptide 19 88 ± 10 N.D. N.D.
NBI 30775 33 ± 4 7.35 ± 0.05 45 nM
NBI 34041 18 ± 5 7.44 ± 0.10 36 nM
NBI 35965 33 ± 3 7.29 ± 0.11 51 nM
NBI 38242 75 ± 10 6.12 ± 0.35 750 nM
NBI 77173 210 ± 20 5.62 ± 0.12 2.4 μM
NBI 77165 210 ± 10 5.62 ± 0.11 2.4 μM
NBI 77178 230 ± 20 5.50 ± 0.24 3.1 μM
NBI 77172 150 ± 10 5.56 ± 0.29 2.7 μM
  • N.D., not determined.