Effect of secretin, glucagon and VIP on gallbladder contraction.

The effects on gallbladder contraction of three structurally related peptides, secretin, glucagon and the vasoactive intestinal peptide (VIP) have been compared in urethane-anesthetized guinea pigs. Secretin and glucagon had no effect alone but augmented cholecystokinin (CCK)-induced contractions. VIP decreased CCK-induced contractions.