Diabetes mellitus is the name given to a group of conditions affecting 194 people worldwide and over 18 million people in the United States. The conditions are linked by their inability to create and/or utilize insulin. Insulin is a hormone produced by the beta cells in the pancreas. It regulates the transportation of glucose into most of the body's cells, and works with glucagon, another pancreatic hormone, to maintain blood glucose levels within a narrow range. Most tissues in the body rely on glucose for energy production, and all but a few – such as the brain and nervous system – are entirely reliant on insulin transportation. Read on to learn more about this disease and what's being done about it.