Topographical distribution of the secretin- and VIP-stimulated adenylate cyclase system in the heart of five animal species.

Adenylate cyclase stimulation by secretin and VIP was compared to the effect of glucagon, D,L-isoproterenol, Gpp[[NH]p, and NaF in atria and ventricles from rat, guinea pig, rabbit, dog and Cynomolgus monkey. In rat ventricular membranes, secretin was a better stimulant than VIP and was as active as D,L-isoproterenol. In rat auricular membranes both peptides were inactive. In guinea pig and rabbit heart membranes (ventricular and auricular) VIP and secretin were inactive. In dog and monkey atria, VIP stimulation of adenylate cyclase was comparable to that of D,L-isoproterenol, secretin being inactive. In dog ventricles, VIP was less efficient than D,L-isoproterenol, secretin being inactive. In monkey ventricles, by contrast, VIP was slightly more efficient than D,L-isoproterenol, secretin having a small effect only in left ventricles. The present results established a clear difference between animal species with respect to the efficacy of the peptides of the secretin/VIP family: the presence of "secretin-preferring" receptors in rat heart contrasted with the presence of "VIP-preferring" receptors in dog and monkey heart. Our results in dog and monkey hearts suggest that VIP might be a candidate for a physiological control of heart function.