Dogs Help Discover Insulin

Dogs were operated on and lost their lives prematurely to greatly improve the lives of those with diabetes.

Charles Best, Frederick Banting and Marjorie

People with type 1 diabetes produce little or no insulin, a pancreatic hormone needed to allow sugar (glucose) to enter cells to produce energy. Before the discovery of insulin therapy, the only effective treatment for the disease was a strict low-calorie, no-carbohydrate diet that led to slow starvation. In 1921, researchers at the University of Toronto began a series of experiments that would ultimately lead to the isolation and commercial production of insulin.

Ten dogs were used in these experiments. Some were used to extract insulin and others were used to become diabetic by removing the pancreas. The extract was injected into the diabetic dogs which caused their blood glucose levels to drop (a good thing). As the experiments proceeded, the researchers realized that they required a larger supply of organs than their dogs could provide so they started using pancreases from cattle. With this new source, they managed to produce enough extract to keep several dogs alive. Marjorie lived the longest, about 70 days (some believed she died of infection caused by her pancreatectomy.) In January 1922, after research allowed the insulin to be purified to be clean enough for testing on humans, a 14 year old boy was chosen as the first person with diabetes to receive insulin. The boy who was near death rapidly regained his strength and appetite. Other volunteer diabetics reacted just as positively as the boy to the insulin extract.

In 1923, Dr. Frederick Banting (the lead researcher) was awarded the Nobel Prize in Physiology or Medicine. It is reported that Banting loved dogs and it pained him deeply that his pre-human insulin trials were conducted on unsuspecting canines. Despite the long hours and no salary, Banting and his colleague Charles Best took very good care of the dogs. According to Dr. S.M. Sadikot, Consultant in Diabetes, Endocrinology and Metabolic Disorder, Jaslok Hospital and Research Center, Mumbai, "During this period, the dogs were more than experimental animals. They became friends, the dogs seemed to understand the importance of the experiment and were certainly, according to the history, most co-operative with the experiments."