islets of Langerhans; pancreatic islets

Function

Cell types:

• alpha cells produce glucagon (15-20% of total islet cells)
• beta cells produce insulin & amylin (65-80%)
• delta cells produce somatostatin (3-10%)
• epsilon cells produce ghrelin (<1%)
• PP cells produce pancreatic polypeptide (3-5%)

Paracrine feedback:

• insulin: secreted by beta cells, inhibits alpha cells
• glucagon: secreted by alpha cells, inhibits beta cells & delta cells
• somatostatin: secreted by delta cells, inhibits alpha cells & beta cells

Structure

• regions of the pancreas that contain endocrine cells, the islet cells
• constitute ~1-2% of the mass of the pancreas
• ~1,000,000 islets are distributed throughout a healthy adult human pancreas
• combined mass is 1-1.5 grams

Pathology

• islet cell transplantation for type 1 diabetes

Notes

not to be confused with Langerhans cell

More general terms

• endocrine gland

Additional terms

• Langerhan's cell

Component of

• pancreas

Components

• islet cell