Insulin stops blood glucose levels from rising too high by causing glucose to move out of the bloodstream and into the cells, and by interfering with the synthesis of new glucose. Diabetics with type 1 diabetes have to use insulin to control their blood glucose levels, while diabetics with diabetes mellitus type 2 may or may not need this medication.
Insulin
Insulin is a hormone secreted by the beta cells of the pancreas to prevent the glucose level in the bloodstream from becoming too high. People develop diabetes mellitus when a high blood glucose level occurs from not having enough insulin, as explained by Douglas Paauw, M.D. in the "Internal Medicine Clerkship Guide." In diabetes type 1, the beta cells are destroyed, while people with type 2 have enough insulin, but not enough to overcome the insulin resistance of the cells.
The Actions of Insulin
Once insulin enters the bloodstream, it attaches to proteins on a cell membrane or within the cell that do whatever they are told. As Elizabeth Corwin, Ph.D. explains in the "Handbook of Pathophysiology," the attachment of insulin causes a series of steps to take place, resulting in the glucose moving from the bloodstream into the cells. In addition, insulin interferes with the production of glucose by the liver and interferes with the breakdown of stored glucose, protein and fats -- all of this lowers the blood glucose level.
Diabetes Mellitus and Insulin
Diabetics with diabetes type 1 must use insulin to control their blood glucose levels because their beta cells do not work at all, while people with type 2 take oral medications and may only need to take insulin if the oral medications no longer prevent the blood glucose level from rising too high. There are several types of insulin and each type is based upon how fast it starts to work.
The Types of Insulin
According to the Merck Manuals Online Medical Library, the insulin called rapid-acting starts to work within 5 to 15 minutes, and will last for three to five hours. This includes insulin with the brand names of Humalog, NovoLog and Apidra. Short-acting insulin takes 30 to 60 minutes to work, but lasts 6 to 8 hours. Humulin is a short-acting insulin. Humulin N and Novolin N are referred to as intermediate-acting insulin because they take 2 to 4 hours to begin to work and last 12 to 26 hours. Lantus and Levemir start to work in 1 to 2 hours, last 14 to 24 hours and are called long-acting insulin.
References
- "Handbook of Pathophysiology"; Elizabeth Corwin, MSN, Ph.D., FNP; 2000
- "Internal Medicine Clerkship Guide"; Douglas Paauw, M.D., Lisanne Burkholder, M.D., Mary Migeon, M.D.; 2003
- Merck Manuals Online Medical Library; Diabetes Mellitus; August 2007
