Choleretic effect of vasoactive intestinal peptide.

Vasoactive intestinal peptide, VIP, was administered intravenously as 10-minute infusions, dosage 0.05 and 0.5 mug/kg/min, to anaesthetized dogs provided with common duct fistulas. When VIP was given to fasting animals, the output of bile, sodium and amylase increased significantly, the bile output by approximately 200% of the control. The biliary concentration of sodium was constant, while that of amylase decreased. When VIP was given to animals, which were fed before the experiment, the bile output was essentially unaffected. The two doses used gave equal peak responses, but the duration of the effect was doubled or trebled following the highest dosage.