Importance of the Amino Acid in Position 15 of VIP and Secretin in Influencing their Interactions with Membrane Receptors on Pancreatic Acinar Cells

1980 Endocrinologia Japonica  
Synopsis To explore the importance of the charge of the amino acid in position 15 in influencing the apparent affinities of VIP and secretin for their receptors on pancreatic acinar cells, we tested the synthetic C-terminal 23-peptide fragment of secretin (S5-27) and two analogues containing substitutions in position 15 for their abilities to interact with secretin-preferring and VIP-preferring receptors on pancreatic acinar cells. In inhibiting the increase in cyclic AMP caused by VIP acting
more » ... rough the VIP-preferring receptors, 15-Lys-55-27 was equipotent with 15-Asn-S5_27, and these analogues were significantly more potent than S5-27. In inhibiting the increase in cyclic AMP caused by secretin acting through the secretin-preferring receptors, S5-27 was equipotent with 15-Asn-55-27, and these peptides were significantly more potent than 15-Lys-S5-27. These findings indicate that the affinities of these 23-peptides for the VIPpreferring receptors and for the secretin-preferring receptors were influenced primarily by the absence of a particular charge in position 15 but not by the presence of the opposite charge. GARDNER et al. Endocrinol. Japon. December 1980
doi:10.1507/endocrj1954.27.supplement_1 pmid:6262063 fatcat:da6c3uygv5dajhln6envhayoze