The discovery of insulin is one of the greatest accomplishments of medical research. This discovery has saved many lives to this day. Who made this discovery, and how? On October 31, 1920, Frederick G. Banting, a surgeon in Canada, had an idea: collect a helpful fluid from the pancreas of healthy animals and inject it into unhealthy animals. The next week, he met with scientist John J.R. Macleod in Toronto, Canada, and they developed a research plan. By August, 1921, Banting and his student assistant, Charles Best, prepared an effective extract from a dog’s pancreas. In January 1922, biochemist James B. Collip purified the insulin enough so that it was ready for human use. They then tested their discovery in human patients with diabetes. On January 23, 1922, Leonard Thompson, a 14-year-old patient with type 1 diabetes at Toronto General Hospital, responded spectacularly to injections of a purified insulin extract. While the work of many scientists laid the foundation for the discovery of insulin, in 1923, Banting and Macleod received the Nobel Prize in Physiology or Medicine for their contributions to the discovery of insulin.


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