Glucose's access to body tissues is regulated by insulin. Insulin is created within the pancreas in specialized "beta" cells. Beta cells are located in the pancreas in a section called the "islets of Langerhans." Insulin is produced only in these islet cells because the gene designated for making insulin is activated exclusively at this site. Once made, insulin is sent to the tissues to permit entry of glucose into cells.
Islet Dysfunction in Type 2 Diabetes
Upon reaching the tissues, insulin must signal its arrival. In type 2 diabetes, this signaling fails and insulin cannot push glucose into the cells. Because the blood glucose level remains elevated, the islet cells continue to produce insulin in increased quantities. Over time, overproduction of insulin causes islet cell fatigue, resulting in eventual underproduction of insulin and worsening of the diabetic condition.
Islet cell fatigue is managed medically through medications that either act at the tissues to facilitate insulin signaling or demand that beta cells produce more insulin. In extreme cases, insulin injections may be necessary.
Obesity is a key factor in signaling failure at the tissues, so managing weight is critical. Balancing energy intake and expenditure through diet and exercise promotes correct signaling of insulin, lowers the workload on the islet cells, and reduces the need for medications.
Islet Dysfunction in Type 1 Diabetes
In type 1 diabetes, miscommunication between the beta cells and the immune system during youth causes beta cell destruction, resulting in permanent need for insulin injections.