Somatostatin is a type of peptide hormone that is found all over the body and plays a significant role in regulating both endocrine and nervous system activities. This hormone can also be detected in endocrine cells of the gastrointestinal tract, bronchopulmonary regions, thymus, and C-cells of the thyroid. Anti-somatostatin serves as an important indicator of D-cells in the pancreatic islets. It identifies cells that contain somatostatin in pancreatic tumors, islet cell overgrowth, and islet cells that come from pancreatic ductules.