The pancreatic islets of Langerhans secrete which hormones?

• A. Glucagon and insulin
• B. Insulin and glucagon
• C. Somatostatin and ghrelin
• D. Epinephrine and norepinephrine

Answer: (B)

The key idea is the endocrine role of the pancreatic islets in glucose regulation. The islets contain alpha cells that secrete glucagon and beta cells that secrete insulin. Insulin lowers blood glucose by promoting uptake and storage of glucose, while glucagon raises it by signaling the release of glucose from liver stores. Though delta cells produce somatostatin, which modulates the activity of insulin and glucagon, the pair most fundamentally associated with the islets’ hormonal function is insulin and glucagon. The other options include hormones not produced by the islets (like ghrelin from the stomach and epinephrine/norepinephrine from the adrenal medulla), or a combination that doesn’t represent the main pancreatic islet hormones. Therefore, the correct pairing is insulin and glucagon.