The effect of histamine, H1 and H2 agonists, and H1 and H2 antagonists on postprandial pancreatic polypeptide release in dogs.

The influence of histamine, H1 and H2 agonists (2-AETD and dimaprit), and H1 and H2 antagonists (mepyramine and cimetidine) on the postprandial release of pancreatic polypeptide (PP) was assessed in five Labrador retrievers. Infusions of histamine, 0.25 mumol kg-1 h-1; 2AETD, 4 mumol kg-1 h-1; and dimaprit, 1 mumol kg-1 h-1, enhanced postprandial release (131-189% of control values). The response to 2-AETD and dimaprit was significantly different from control values (p less than 0.05). An increase was observed even when 50 mg mepyramine and 400 mg cimetidine were injected as intravenous boluses (131-139% of control values (p less than 0.05]. The action of the antagonists may be explained by partial agonism or histamine release induced by these agents. It is concluded that postprandial PP release is stimulated by H1 and H2 receptors.