This potted history of diabetes and insulin is here purely because I thought it was interesting - please feel free to ignore it!
Diabetes Mellitus has been around since the dawn of time. Ancient Egyptians knew of it, as did ancient Greeks. An ancient Egyptian scroll called The Ebers Papyrus goes into great detail about the condition. They didn’t know what caused it. All they knew was that it killed you.
A Greek physician called Aretaeus Of Cappadocia named the illness, from Greek diabainein, (to pass through) and from Latin Mellitus, (sweetened with honey). The term diabetes is also Greek for "siphon" and Aretaeus is attributed with saying that diabetes “is a disease in which the flesh melts away and is siphoned off in the urine.” He further described it as “a wonderful affliction … a melting down of the flesh and limbs into urine… life is short, disgusting and painful, thirst unquenchable, death inevitable… ”
Nothing was known about the cause until 1788 when a post-mortem examination on a diabetic showed that the pancreas had atrophied. In 1869 a medical student called Paul Langerhans, identified small groups of specialised cells in the pancreas - cells which were later shown to be the source of insulin. These specialised cells were named after him and are known as “The islets of Langerhans”. The real breakthrough occurred in 1889 when it was noted that a dog whose pancreas had been removed developed all the classic diabetes signs. Research workers were therefore able to establish that removal or destruction of the pancreas caused diabetes.
The death sentence for diabetics was finally lifted in 1922 when two Canadian scientists, Frederick Banting (1891-1941) and Charles Best (1899-1978) took fluid from animal pancreases, purified it, and injected it into Leonard Thompson, an 11-year-old boy suffering from severe diabetes. Leonard was close to death and weighed only 34 kilograms.
After injections of the fluid, his blood sugar levels went down, he was able to eat a more normal diet, he gained weight, and he lived to be an adult.
Because this hormone came from groups of cells (called “islets”) in the pancreas, Banting and Best wanted to call it ’isletin’. The head of their laboratory suggested they use the Latin term insula, meaning ’an island’ and the word insulin was born.