Isolation and partial sequence of elasmobranch VIP.

We have used a combination of gel filtration, ion exchange chromatography and reversed-phase HPLC to isolate and characterize a VIP-related peptide from the gut of the elasmobranch Scyliorhinus canicula. The N-terminal decapeptide of the Scyliorhinus material was identical with that of porcine VIP. However, Scyliorhinus VIP did not cross react with antisera specific for the C-terminus of porcine VIP. Like porcine VIP, Scyliorhinus VIP was a potent stimulant of exocrine pancreatic secretion in the turkey, but the response to Scyliorhinus VIP had a shorter duration. VIP from a second elasmobranch, Squalus acanthius was partially purified, and had biological and immunochemical properties similar to those of Scyliorhinus VIP. The results indicate that elasmobranch VIP is identical to porcine VIP at its N-terminus, but differs at the C-terminus. These structural differences may influence the rate of metabolism of the peptide.