Fig. 1.

Comparison of the affinities of the peptide agonists GRP, NMB, and peptide #1, nonpeptide agonist MK-5046, and the putative peptide antagonist Bantag-1 for the hBRS-3–receptor in (A) hBRS-3 Balb 3T3 cells and (B) NCI-N417 cells. The peptides were incubated with 50 pM ¹²⁵I-[d-Tyr⁶,β-Ala¹¹,Phe¹³,Nle¹⁴]Bn-(6–14) for 40–60 minutes at 21°C in 300 μl of binding buffer with hBRS-3 Balb 3T3 cells (0.5 × 10⁶ cells/ml) or NCI-N417 cells (1 × 10⁷ cells/ml), and the saturable binding was determined as described under Materials and Methods. The results are expressed as the percentage of saturable binding without unlabeled peptide added (percentage control). The results are the mean ± S.E.M. from at least four experiments, and in each experiment the data points were determined in duplicate.