Pancreatic Polypeptide (PP) is a 36-amino acid anorexigenic peptide hormone secreted by the PP cells of pancreas. It is rapidly released postprandially and continues to remain elevated for approximately 4-6 hours after a meal. PP modulates food intake, and is absent in children with Prader-Willi syndrome. Secretion of PP can be accomplisehd through electrical stimulation of the vagus nerve. Cholecystokinin (CCK) and Gastrin appear to be involved in its secretion, while Ghrelin and Obestatin are reported to inhibit its release. PP is related to Peptide YY and Neuropeptide Y (NPY).