Pancreatic polypeptide.

Pancreatic polypeptide (PP) was discovered fortuitously during the purification of insulin from birds (Kimmel et al., 1968) and later from mammals (Chance et al., 1976). PP has since been extracted and purified from several mammalian species. It contains 36 amino-acid residues and is quite distinct from other known hormonal peptides (Lin and Chance, 1974). The amino-acid sequence of the peptides extracted from man, pig, dog, sheep, and cow differs only in one or two residues in positions 2, 6, or 23 (Lin and Chance, 1974). The biological activity of these mammalian peptides has been found to reside in the C terminal hexapeptide (Lin and Chance, 1978). Rodent PP, however, appears to be somewhat different in that it does not cross-react with the majority of antisera raised to the bovine peptide.