Delta cells secrete which hormone to regulate other islet hormones?

• A. Glucagon
• B. Insulin
• C. Somatostatin
• D. Amylin

Answer: (C)

Delta cells produce somatostatin, which acts as a paracrine regulator within the pancreatic islets. Somatostatin dampens the release of neighboring hormones from alpha and beta cells, helping to fine-tune the balance between glucagon and insulin as blood glucose changes. In other words, somatostatin from delta cells serves to prevent excessive fluctuations by inhibiting both insulin and glucagon when appropriate. Glucagon comes from alpha cells and raises glucose, insulin from beta cells lowers glucose, and amylin is co-secreted with insulin from beta cells—none of these are produced by delta cells.