Diabetes mellitus has been a scourge of the developed world with an estimated 400,000,000 people worldwide suffering from this disease, and 50% more predicted within twenty years. Its early symptoms, which include increased thirst and large volumes of urine, were recognized as far back as 1500 BCE in Egypt. While the term diabetes, meaning “to pass through,” was first used in 250 BCE by the Greek physician Apollonius of Memphis, Type 1 and Type 2 diabetes, associated respectively with youth and obesity, were identified as separate conditions by Indian physicians somewhere in the 5th century CE. But despite the disease being known, a diagnosis of diabetes in a human patient would remain tantamount to a death sentence until the early 20th century, its causes unknown.
What changed this dire situation was the help of humanity’s longtime animal partner: Canis lupus familiaris, domesticated from Grey wolves thousands of years ago. In 1890, the German scientists Von Mering and Minkowski demonstrated that removing a dog’s pancreas caused it to develop all the signs of diabetes, thus establishing the organ’s central role in the disease. But the exact mechanism by which this occurred remained a mystery until 1920, when a young Canadian surgeon named Frederick Banting and his student, Charles Best, advanced the findings of their German colleagues. Working under Professor Macleod at the University of Toronto, they confirmed that the pancreas was responsible for regulating blood glucose, successfully treating diabetic dogs by injecting them with an extract they had prepared from pancreas tissue.
By 1922, the researchers working with biochemist James Collip were able to develop a similar extract from beef pancreas to first treat a 14-year-old diabetic boy, followed by six additional patients. The manufacturing process for this extract, now known as insulin, was eventually turned over to a pharmaceutical company that makes different types of injectable insulin to this day. Banting and Macleod received the Nobel Prize for Medicine in 1923 for their discovery. But Banting chose to share his portion with Charles Best, for his help in the initial studies involving dogs. But while medical experimentation on animals remains controversial, in this case at least, it was not just a matter of exploiting dogs for human needs.
Dogs develop diabetes at the rate of two cases per 1,000 dogs, almost the same as that of humans under 20. Most canine cases are of Type 1 diabetes, similar to the type that young children develop following immune system destruction of the pancreas, and genetic studies have shown that the dog disease has many similar hallmarks of the human disease. This has allowed veterinarians to turn the tables, successfully using insulin to treat diabetes in man’s best friend for over 60 years.
Many dog owners commit to managing their dogs’ diabetes with insulin injected twice daily, regimented feedings, and periodic blood measurements using the same home-testing glucose monitors used by human patients. And if the purified pig insulin commonly used for dogs fails to work for a particular dog, the vet may even turn to a formulation of human insulin, bringing the process full circle. After all that dogs have done for us throughout the ages, including their role in a medical discovery that has saved countless human lives, using that same knowledge to help them is the least we could do.