Endocrine functions of the pancreas... which cells secrete glucagon, which secrete insulin, and which secrete somatostatin, respectively?

• A. Alpha, Beta, Delta
• B. Beta, Alpha, Delta
• C. Delta, Alpha, Beta
• D. Alpha, Delta, Beta

Answer: (A)

Glucagon, insulin, and somatostatin are produced by distinct islet cells in the pancreas. Glucagon is secreted by alpha cells, insulin by beta cells, and somatostatin by delta cells. This sequence—alpha for glucagon, beta for insulin, delta for somatostatin—reflects their roles: glucagon raises blood glucose during fasting, insulin lowers it after meals, and somatostatin modulates the release of both insulin and glucagon while dampening GI hormone activity. The alpha cells are typically located toward the islet periphery, beta cells are the most abundant, and delta cells serve a regulatory paracrine function within the islet.