A Brief History of Insulin

WRITTEN BY: Forester McClatchey

Editor’s Note: People who take insulin require consistently affordable and predictable sources of insulin at all times. If you or a loved one are struggling to afford or access insulin, click here.

If I’d been born a century earlier, my diagnosis would have been a death sentence.

It’s difficult to overstate the direness of diabetes pre-insulin. Though it’s been a known disease since the 16th century BCE, when Egyptian physicians noted that ants were attracted to the urine of certain patients (whose other symptoms would include emaciation, thirst, and exhaustion), for most of human history anyone unfortunate enough to suffer from Type 1 diabetes would almost certainly die.

As recently as 1920, doctors gave newly diagnosed diabetics mere weeks (or days) to live. Fortunate patients might break months, or, in rare cases, a year. But mostly, patients would enter diabetic ketoacidosis (DKA) and die soon after their diagnosis.

A few treatments attempted (feebly) to forestall this eventuality. The most common of these treatments was a starvation diet, which involved near-complete elimination of carbohydrates. This treatment could kill the patient just as surely as their skyrocketing glucose levels.

All this changed in the 1920s.

During the last few decades of the 19th century, scientists had been approaching a loose scientific understanding of diabetes — in 1869, a German medical student named Paul Langerhans discovered clusters of cells, nestled in pancreatic tissue, whose function was unknown. (Later, when it was discovered that these clusters produced insulin, they were named the Islets of Langerhans.) In 1889, two German researchers discovered that removing a dog’s pancreas would provoke severe symptoms of diabetes.

Having detected the immediate cause of diabetes, researchers now had a shot at treating it.

Into this nascent medical world walked the most famous man in diabetic history: a young surgeon from Ontario named Frederick Banting. He’d been reading medical papers that hypothesized insulin, if one could isolate and extract it, might be used to treat diabetes. Along with his assistant Charles Best, Banting was determined to test this theory.

Prior attempts to extract and inject insulin had failed because pancreatic digestive enzymes would destroy the insulin before researchers could use it. In order to surmount this obstacle, Banting tied off (or “ligated”) the pancreatic duct, killing off the insulin-destroying enzymes, but leaving the Islets of Langerhans intact.

Before I go on, I should establish something. The ethical framework within which medical researchers operated in the early 20th century was, shall we say, flexible. If you like dogs, find a seat.

Banting’s procedure involved cutting out a dog’s ligated pancreas, throwing that pancreas in a blender with some saline ice, and then reinjecting the dog with its own pancreas smoothie. (Banting’s idea was not wholly original; two European scientists had attempted similar injecting-dogs-with-their-own-pancreatic-juices projects in 1906 and 1916, each with mixed but promising results.) Were he alive, Banting might take issue with my unsophisticated summary of his research, but he won the Nobel Prize in 1923, so he can deal with it.

Anyway, the procedure worked. That is, the dog did not immediately die, and even recovered some of its strength. Banting and Best collaborated with chemist named James Collip, who invented a way of purifying the dog insulin — without Collip’s purification technique, the results of an insulin injection would vary wildly. After bringing the dog back from the brink of death, however, the trio knew they were onto something important. Once they felt ready, they hastened to test their theories on a human subject.

So, in January 1922, a young Canadian patient named Leonard Thompson became the first human being to receive an insulin injection. He was 14-years-old, 65 pounds, and dying when he received the first famous doses. Despite having an allergic reaction to the dog-insulin, Thompson recovered his strength quickly.

It was not until April of 1922 that researchers began calling the miracle substance “insulin.” The name came from the Latin insula, meaning “island,” since the substance was secreted by the “Isles” of Langerhans.

Eli Lilly and Company took note of the successes of Banting, Best, and Collip, and in 1923 the company began to mass-produce insulin (derived from the pancreases of pigs and cows). They named their product “Iletin.” For the first time in human history, diabetes was not a death sentence.

Still, the diabetic lives that Banting and co. saved remained difficult. Although insulin therapy prevented immediate death, it was still too imprecise to get rid of chronic complications like blindness, nerve damage and kidney failure. The insulin itself, derived from animal pancreases, caused allergic reaction in some patients. Further, for many decades, patients could only test their glycemic levels with urine.

Things gradually improved. In 1950, Novo Nordisk, Inc. introduced the first slow-acting insulin. This allowed for more versatile treatments. The first genetically engineered or “human” insulin became available in 1982. Derived from E. coli bacteria, Eli Lilly began selling it under the brand “Humulin.”

Diabetes treatment is still a very young science, and the era of hope (even tenuous hope) for diabetics has been brief.

Let’s try to put this brevity into perspective. If you’re familiar with the thought experiment that pretends Homo sapiens have been around for 24 hours (Jesus would have been walking around 14 minutes ago, Shakespeare would have been born 3 minutes and 8 seconds ago; you get the idea), then consider this: Insulin has been available to Type 1 Diabetics for less than 40 seconds. For the remaining 23:59:20, diabetes has been lethal.

The thought harrows us. Any diabetic reading this was born into an inheritance of luck, and now enjoys the privilege of mere survival. For most of our species’ history, diabetes brought unalloyed tragedy, but now, during the last few historical moments, the disease’s narrative has swung up, into a comedic trajectory. It’s hard not to be grateful.

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