beta cell

Beta cell
The photo above shows a mouse pancreatic islet as seen by light microscopy. Beta cells can be recognised by the green insulin staining. Glucagon is labelled in red and the nuclei in blue.
An islet of Langerhans in a pig. The left image is a brightfield image created using hematoxylin stain; nuclei are dark circles and the acinar pancreatic tissue is darker than the islet tissue. The right image is the same section stained by immunofluorescence against insulin, indicating beta cells.
Latin	endocrinocytus B; insulinocytus
Code	TH H3.04.02.0.00026

Beta cells (beta-cells, β-cells) are a type of cell in the pancreas located in the so-called islets of Langerhans. They make up 65-80% of the cells in the islets.

Function

Beta cells store and release insulin, a hormone that controls the level of glucose in the blood. The liver maintains the base-line glucose level, but the beta cells can respond quickly to spikes in blood glucose by releasing some of its stored insulin while simultaneously producing more. The response time is very quick.

Apart from insulin, beta cells release C-peptide, a byproduct of insulin production, into the bloodstream in equimolar quantities. C-peptide helps to prevent neuropathy and other symptoms of diabetes related to vascular deterioration.^[1] Measuring the levels of C-peptide can give a practitioner an idea of the viable beta cell mass.^[2]

Beta-cells also produce amylin,^[3] also known as IAPP, islet amyloid polypeptide. Amylin functions as part of the endocrine pancreas and contributes to glycemic control. Amylin's metabolic function is now somewhat well characterized as an inhibitor of the appearance of nutrient [especially glucose] in the plasma. Thus, it functions as a synergistic partner to insulin. Whereas insulin regulates long-term food intake, increased amylin decreases food intake in the short term.

Pathology

• Diabetes mellitus type 1 is caused by the destruction or dysfunction of insulin-producing beta cells by the cells of the immune system.

• In Diabetes mellitus type 2, by contrast, beta cells decline gradually over time, and insulin resistance plays at least as large a role in the disease ^[4][5]

• Insulinoma is a rare tumor derived from beta cells. Insulinomas are usually benign and not malignant, but may be medically significant and even life-threatening due to recurrent and prolonged attacks of hypoglycemia.

Diabetes can experimentally be induced in beta cells for research purposes by streptozotocin or alloxan, which are specifically toxic to beta cells.

See also

• insulin
• amylin
• C peptide
• Gastric inhibitory polypeptide receptor
• ATP-sensitive potassium channel
• List of terms associated with diabetes

References

External links

• MeSH Pancreatic+beta+cells