Anti-Somatostatin is a useful marker of D-cells of pancreatic islet cells. D-cells identification can be used to identify hyperplasia of the pancreatic islets as well as islet cell tumors such as somatostatinomas. Somatostain can also be found in gastrointestinal and bronchopulmonary endocrine cells, thymic endocrine cells, and thyroid C cells. Somatostatin suppresses gastric acid secretion, gallbladder contractions, and pancreatic enzyme secretion.