Changes in plasma levels of gastrointestinal regulatory peptides during hemorrhagic shock in pigs.

In an experimental study of hemorrhagic shock, systemic and portal plasma levels of vasoactive intestinal polypeptide (VIP), somatostatin, pancreatic polypeptide (PP), gastric inhibitory peptide (GIP), secretin and insulin were measured with radioimmunoassay methods. Six pigs (30-40 kg) in general anesthesia were submitted to severe hemorrhage (approximately 30% of the blood volume) for 60 min, followed by reinfusion of the shed blood. Aortic blood pressure and cardiac output fell significantly during the shock state and recovered after the infusion. Plasma levels of somatostatin, PP, insulin and secretin rose significantly. The portal levels always presented earlier and greater elevation than did the systemic levels, except as regards secretin. No change was seen in the levels of VIP and GIP.