November 25, 2009
4 min read

Frederick Banting discovered insulin in 1921

Insulin, the first available medicine for the treatment of diabetes, changed the meaning behind the diagnosis.

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Frederick Banting’s role in the discovery of insulin is undisputed.

However, for many decades, the role of each of the other three men involved — Charles Best, J.J.R. Macleod and James Bertram Collip — was disputed by many.

Despite anyone’s personal opinion, the discovery of insulin during the summer of 1921 was one of the most influential discoveries in medical history, and the idea behind it was Banting’s. Although he lacked knowledge of diabetes and clinical research, his unique knowledge of surgery, combined with Best’s knowledge of diabetes, made for the perfect research collaboration.

Insulin, the first available medicine for the treatment of diabetes, changed the meaning behind the diagnosis. People with type 1 diabetes could thereafter expect a longer, richer life.

A big idea

Banting was born in 1891 in Ontario, Canada. He attended Victoria College, a school for ministry at the University of Toronto. After a little more than a year, he transferred his focus from ministry to medicine.

Once he earned his medical degree, he was sent overseas with the Royal Canadian Army Medical Corp to fight in World War I. At the end of the war in 1919, he returned to Toronto and became a resident of surgery at the Hospital for Sick Children. During his time there, Banting gained a thorough understanding of surgery, mostly orthopedic, and anesthesia. Shortly after, he left the hospital to open a general surgical practice in London, Ontario.

By this time, Banting was about 27 years old. His slow practice in London was a financial concern, and he often expressed dreams of important or groundbreaking research in his personal journals.

The night before he was to give a lecture on the topic of the pancreas, Banting’s interest in diabetes and pancreatic extract was sparked by an otherwise unremarkable article in Surgery, Gynecology and Obstetrics, “The relation of the islets of Langerhans to diabetes, with special reference to cases of pancreatic lithiasis.” In it, the author writes about the discovery of a stone blocking a pancreatic duct. Blocking of pancreatic ducts led to the atrophy of the externally secreted acinar cells, leaving the internally secreted islet cells intact.

Banting had an idea to intentionally ligate pancreatic ducts, allowing time for the acinar cells to degenerate, leaving just the islet cells. He posited that isolating this internal secretion, which was already proven to help metabolize sugar, could be a treatment for diabetes.

Other experiments with the extract of the pancreas had been conducted throughout the first two decades of the 20th century, but no one has been able to eliminate the toxic reactions that followed after treatment initiation. This would prove to be the key to treating diabetes with insulin.

A new experiment

The institution where Banting worked in London, Ontario, was not set up to conduct the type of large experiments that he would require to prove his theory. He was advised by a mentor to go to the University of Toronto and speak with Macleod, a well-known physician in the field of metabolism and diabetes. After much discussion, Macleod offered Banting a chance to conduct his experiments at the University of Toronto during the summer months of 1921.

In May, Banting closed his practice in London and set out for Toronto. Upon his arrival, a student assistant was assigned to him; Best was a senior in the physiology and biochemistry programs and had thorough knowledge of diabetes and the analysis of blood glucose. The partners would atrophy the pancreas of healthy dogs until the acinar cells were dead, then remove the pancreas and try to extract the islet cells to administer to dogs whose pancreases had been removed.

Months of experiments brought them closer to a solution, and in December 1921, Banting, Best and Macleod had in their hands an extract from whole beef pancreas mixed with alcohol that successfully lowered the blood glucose levels in a dog whose pancreas had been removed.

Enter Collip, who would help the team to purify its insulin extract. This purified version would prove successful in the clinical trials conducted on patients with diabetes at Toronto General Hospital.

Announcing it to the world

In early 1922, the group of researchers published their preliminary finding in the Canadian Medical Association Journal, “Pancreatic extract in the treatment of diabetes mellitus.” In it, they tentatively announced that the extracts they had isolated will have a great value in the treatment of diabetes.

A strong belief in its therapeutic value drove the team of researchers to begin to think about production on a mass scale; however, they encountered many problems in producing the hormone in large quantities. Eventually an offer of help from Eli Lilly and Company was accepted, and Banting and Best traveled to Indianapolis to work with company chemists to produce the revolutionary extract insulin.

On Jan. 23, 1923, Banting, Collip and Best were awarded U.S. patents on insulin and the method used to make it. They all sold these patents to the University of Toronto for $1 each.

Later that year, Banting and Macleod were awarded the Nobel Prize in medicine for the discovery of insulin. Banting is said to have felt as though Best, and not Macleod, should have had the privilege of sharing the award with him. Banting later announced that he would share both the cash and the credit with Best. Shortly after that, Macleod announced that he would share his half of the award with Collip.

This was just one of the many times that these men would dispute the role of each researcher in the discovery of insulin. In fact, the relationship between these four men was often strained due to accusations of false or misleading credit.

After insulin

After he left the University of Toronto, Banting remained active in research, but none of it involved insulin. In fact, Banting was the only one of the team of insulin discoverers who did not go on to accomplish any additional significant research. Excerpts from Banting’s journals show a continuous struggle to produce another great medical discovery, which never came.

When World War II began in 1939, Banting served as a coordinating chairman of Canada’s wartime medical research; he focused on aviation medicine. During one of the transatlantic trips to Britain related to this position, Banting died in a plane crash on Feb. 21, 1941. – by Leah Lawrence

For more information:

  • Bliss M. Dr. Frederick Banting: getting out of town. Can Med Assoc J. 1984;130:1215-1223.
  • Katz S. A new, informal glimpse of Dr. Frederick Banting. Can Med Assoc J. 1983;129:1229-1232.
  • Madeb R, Koniaris LG, Schwartz SI. The discovery of insulin: the Rochester, New York, connection. Ann Intern Med. 2005;143:907-912.
  • Rafuse J. Seventy-five years later, insulin remains Canada’s major medical-research coup. Can Med Assoc J. 1996;155:1306-1308.
  • Rosenfeld L. Insulin: discovery and controversy. Clinical Chemistry. 2002;48:2270-2288.