What roles do alpha and delta cells play in glucose regulation?

• A. Alpha cells secrete insulin; delta cells secrete glucagon.
• B. Alpha cells secrete glucagon (raises glucose); delta cells secrete somatostatin (inhibits insulin and glucagon release and slows GI function).
• C. Alpha cells produce amylin; delta cells produce incretins.
• D. Alpha cells secrete cortisol; delta cells secrete glucagon.

Answer: (B)

Alpha cells release glucagon, which raises blood glucose by signaling the liver to break down glycogen and to produce glucose from non-carbohydrate sources. This is especially important during fasting or between meals when glucose levels tend to drop. Delta cells secrete somatostatin, which dampens the release of both insulin and glucagon and also slows gastrointestinal function, helping fine-tune the overall regulation of glucose and digestion.

That alignment—alpha cells secreting glucagon to raise glucose and delta cells secreting somatostatin to modulate hormone release and GI activity—explains why this is the best description of their roles. For context, insulin is produced by beta cells, amylin is co-secreted with insulin by beta cells, incretins come from the gut, and cortisol is produced by the adrenal cortex, not by pancreatic islet cells.