Which organ produces insulin?

The pancreas, in scattered clusters of cells called the islets of Langerhans that make up only about one or two per cent of the organ - the rest produces digestive enzymes. Insulin's job is to let glucose into cells, and without it the body starves in the middle of plenty, with sugar accumulating in the blood while the tissues cannot reach it.

Before 1922 type 1 diabetes was a death sentence in months, and the only treatment was a starvation diet that bought a little time at terrible cost. Frederick Banting and Charles Best extracted insulin from dog and then cattle pancreases in Toronto; the first patient, a fourteen-year-old boy weighing about 29 kilograms, recovered within days. Banting, Best and their colleagues sold the patent to the University of Toronto for one dollar each, on the explicit reasoning that it belonged to the world.

That decision has aged into an indictment. Insulin is now made by genetically modified bacteria - the first medicine ever produced that way, from 1978 - and costs very little to manufacture, while list prices in the United States rose to the point that people were rationing it and dying. Banting is quoted as saying insulin does not belong to me, it belongs to the world, which is now cited in congressional testimony rather more often than in medical history.