Diabetes mellitus (Type 1) is a disease which results from the inability of the pancreas to produce insulin, which regulates the uptake of sugar to the body's cells. As a result, sugar builds up in the blood until the patient goes into a coma. Although there are other diseases called diabetes, this form of the disease is what is usually meant when no other word is used to modify it. Until the early 20th century, a diagnosis of diabetes meant certain death. However, the discovery that there was a hormone produced by the pancreas known as insulin and its subsequent isolation allow diabetics to lead fairly normal lives. The isolation of insulin also gave birth to the modern medical science of endocrinology.