In a laboratory in Toronto, a dog became the first evidence that diabetes could be influenced with a pancreatic extract. On July 27, 1921, Canadian physician Frederick Banting and medical student Charles Best extracted a substance from the pancreas of a dog with its pancreatic ducts tied off and injected it into another animal in which diabetes had been induced. Its blood sugar fell, and its overall condition improved.
This was not the first time fully purified insulin had been obtained, but rather the first decisive experiment with an active pancreatic extract. The scientific work began on May 17, 1921, in the laboratory of physiologist John Macleod at the University of Toronto. Macleod provided the facilities, animals and scientific guidance, while Banting and Best conducted the main series of experiments during the summer.
From the dog experiment to the first patient
The team gradually established that the extract could keep diabetic animals alive. At the end of 1921, biochemist James Collip joined the project. He worked on purifying the substance and preparing it for testing on humans. This step turned a promising laboratory result into a possible treatment.
On January 11, 1922, 14-year-old Leonard Thompson became the first person to receive an insulin extract in Toronto. The initial preparation did not produce a sufficient result, but after further purification, his condition improved. The case showed that the discovery could also be applied to severe forms of diabetes.
The publication came in 1922
In widely circulated historical accounts, July 27, 1921, is often cited as the date when the active extract was first successfully isolated. The scientific publication of the results, however, began in 1922. Among the early reports was the article “Pancreatic Extracts in the Treatment of Diabetes Mellitus,” published in March in the Canadian Medical Association Journal.
The Nobel Committee awarded the 1923 Nobel Prize in Physiology or Medicine to Banting and Macleod, with the citation: “for the discovery of insulin”. The decision angered Banting, who believed that Best should be recognized alongside him. He shared his prize money with his young colleague. Macleod did likewise and shared his portion with Collip.
Thus, the history of insulin remains not only the story of a scientific breakthrough, but also an example of a discovery built by a team. Banting and Best initiated the experiments, Macleod provided the scientific environment, and Collip helped make the extract suitable for use in humans.
Sources: history.com, smithsonianmag.com