The discovery of insulin

Today marks the 90th anniversary of the first time insulin was used on a human patient.

A brief summary of this event runs as follows: the insulin was injected into a 14-year old diabetic, Leonard Thompson, at Toronto General Hospital. Insulin had been discovered in 1921 at the University of Toronto by Canadian doctor Frederick Banting and American biomedical scientist Charles Best. Thompson’s condition had worsened in late 1921 and when he was admitted to hospital he weighed only 65 pounds. With the risk of him slipping into a diabetic coma, Thompson’s father let the hospital try the new pancreatic extract for the first time.

As a biography of Thompson on the Science Museum’s Brought to Life website notes:

“The extract was an impure form of insulin. Thompson had an allergic reaction, and it had little effect.

A few days later Thompson was injected with a purer form of insulin. This was extracted by the chemist James Collip. Thompson’s blood sugars gradually returned to normal and his diabetic symptoms began to disappear. News of Thompson’s recovery spread, inspiring people with diabetes and their families to write letters to Banting and Best asking for urgent treatment”.

So, a medical breakthrough: treatment for diabetes was revolutionised and a terminal disease became treatable. Banting received the Nobel Prize in Medicine in 1923 and as a result of these developments, the lives of millions were changed for the better.

What this quick summary skates over, however, were the politics and powerplays that went on behind the scenes, with disagreements over who could claim success for the development of insulin. What role was played by Prof John Macleod, Professor of Physiology at the University of Toronto, who granted Banting a laboratory at the University to conduct his research (it was with MacLeod, not Best, that Banting shared his Nobel Prize)? And what of Collip, who purified the insulin?

The most detailed account of these discoveries is The discovery of insulin by Michael Bliss (2007 ed), but the Wellcome Library also holds a file of papers which casts an interesting light on these debates.

This comes in the form of copies of letters passed on to the Wellcome Library in 1959 by Sir Henry Dale – Chairman of the Wellcome Trust and also one of the most respected scientists of his time. The letters include accounts of the discovery of insulin by both Banting and MacLeod and illustrate their divergent views. The file also includes a summary of its contents written by Dale himself, offering his own perspective on events.

Leaving aside the actual details of these letters, we’d merely like to flag up this file as an example of how medical breakthroughs have rarely been the result of the efforts of one lone scientist, and that disagreements over recognition by both public and peers can cloud the achievements of scientists.

It’s also noteworthy that the papers, whilst focusing on the discovery of insulin and setting out the achievements of Banting, MacLeod, Collip and Best, make very little mention of the use of insulin to treat Leonard Thompson.

Image: Leonard Thompson, from the site ‘The Discovery and Early Development of Insulin‘ from Digital Collections of the University of Toronto