Dorothy Hodgkin's model of pig insulin, c.1967

Insulin is a protein hormone, produced in the pancreas, which regulates the metabolism of glucose, fats and proteins. It was discovered in 1921 by the Canadian physician Frederick Banting (1891-1941), who pioneered the use of insulin for the treatment of diabetes. Insulin was the first protein to have its molecular structure completely established, by X-ray crystallographer Dorothy Crowfoot Hodgkin (1910-1994) in 1969. This model of pig insulin's molecular structure clearly shows its complexity.