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Discovery of the Islets of Langerhans
Paul Langerhans finds clusters of cell with an unknown function within the pancreatic tissue that produces digestive juices, which turn out to be insulin-producing beta cells. The cell clusters are later named islets of Langerhans. -
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The Discovery of Insulin
Before the discovery of insulin, diabetes was a feared disease that almost always led to death. Here's how this life-saving invention came to be. -
Minkowski and von Mering Experiments
Oskar Minkowski and Joseph von Mering show that if the pancreas is removed from a dog, it develops diabetes, but when the duct through which the pancreatic juices flow to the intestine was ligated - surgically tied off so the juices couldn't reach the intestine - the dog developed minor digestive problems but no diabetes, therefore finding that the pancreas had at least two main functions. -
Dr. Frederick Banting's Theory
Dr. Frederick Banting, a Canadian surgeon, believed that the pancreatic digestive juices could be harmful to the secretion of the pancreas produced by the islets of Langerhans. He wanted to ligate the pancreatic ducts, which would cause the pancreas to degenerate, making it shrink and lose its ability to secrete the digestive juices. He thought that the cells would produce an antidiabetic secretion that could then be extracted from the pancreas without being harmed. -
Banting and Best
Banting took his idea to Professor John Macleod at the University of Toronto, a leading figure in the study of diabetes in Canada. Macleod didn’t think that Banting’s theories were great, but Banting managed to convince him to give it a go. Macleod gave Banting a laboratory with a minimum of equipment and ten dogs. Banting also got an assistant, a medical student by the name of Charles Best. The experiment was set to start in the summer of 1921. -
The Experiments Begin
Firstly, Banting and Best removed the pancreas from a dog and noted that the dog then developed diabetes. They then surgically ligated the pancreas of another dog, which degenerated. Soon, they removed the pancreas, grounded it up, and filtered it, discovering the substance ‘isletin’. This was regularly injected into the dog with diabetes, which reduced its symptoms and kept it healthy. Banting and Best showed their result to Macleod, who wanted more tests to prove the extract really worked. -
Macleod gives more funding; Collip joins team
Macleod gave more funding to Banting and Best, and they started experimenting with the pancreases of cattle, which contained enough insulin to keep several dogs alive. Macleod suggested they call the pancreas extract ‘insulin’. A biochemist named Bertram Collip joined their team. He was tasked with purifying the insulin so it would be clean enough to test on humans. -
Human Testing
Banting and Best begin to test the extract on themselves, feeling weak and dizzy, but not harmed. Collip continued his work, trying to find the right dosage for humans, and realised that the glucose had to be as pure as possible. A fourteen year old boy, Leonard Thompson (in picture), from Toronto, Canada, was chosen as the first person with diabetes to receive the insulin, which was a great success. They began testing on a wider range of volunteer diabetics, who all reacted positively. -
Nobel Prize and Legacy
The Nobel Committee decide to award Banting and Macleod the Nobel Prize in Physiology or medicine. Banting was furious, as he felt that the Nobel Prize should have been given to him and Best, not him and Macleod, so he split his prize money with Best while Macleod split his with Collip. The medical firm Eli Lilly started producing the extract, soon making enough insulin to provide for the whole of North America.
