Which of the following cell types in the endocrine pancreas (islets of Langerhans) are correctly matched: Alpha cells with glucagon, Beta cells with insulin, or Delta cells with somatostatin?

Pancreatic Islet Cell Types and Hormone Secretion

Beta cells secrete insulin, making option B the only correct match among the choices provided.

Correct Cell-Hormone Pairings

The endocrine pancreas contains three major cell types within the islets of Langerhans, each producing distinct hormones:

Beta Cells → Insulin

• Beta cells are the sole producers of insulin in the human body, which is secreted in response to glucose and other nutrients 1
• Beta cells constitute the dominant cell population in pancreatic islets and are responsible for glucose-stimulated insulin secretion through ATP-dependent closure of K_ATP channels 2
• Insulin secretion occurs in a biphasic pattern: a rapid first phase within 3-5 minutes, followed by a sustained second phase lasting 60-120 minutes 3

Alpha Cells → Glucagon (NOT Somatostatin)

• Alpha cells secrete glucagon, not somatostatin 1
• Glucagon is released in response to hypoglycemia and acts to increase blood glucose through hepatic glycogenolysis and gluconeogenesis 1
• Alpha cells express CFTR channels and their glucagon secretion is inhibited by both insulin and somatostatin 1

Delta Cells → Somatostatin (NOT Glucagon)

• Delta cells are the source of somatostatin within pancreatic islets 1
• Somatostatin exerts tonic inhibitory control over both insulin and glucagon secretion, serving as a key paracrine regulator 4, 5
• Delta cell somatostatin secretion is stimulated by glucagon via glucagon and GLP-1 receptors, creating a reciprocal feedback loop 4

Analysis of Answer Choices

Option A is incorrect: Alpha cells produce glucagon, not somatostatin 1

Option B is correct: Beta cells produce insulin, which is well-established across all evidence 1, 2, 6

Option C is incorrect: Delta cells produce somatostatin, not glucagon 1, 4, 5

Options D and E are incorrect because they include incorrect pairings from options A and C

Paracrine Regulation Context

The three cell types function in coordinated fashion through extensive paracrine crosstalk:

• Somatostatin from delta cells inhibits both insulin and glucagon secretion at all glucose levels 4, 5
• Glucagon from alpha cells stimulates somatostatin secretion approximately twofold 4
• Beta cells release Urocortin 3 at high glucose to stimulate delta cells, creating negative feedback 7
• This intraislet communication is essential for precise glucose homeostasis, and its breakdown contributes to diabetes pathophysiology 8