The insulin hormone is secreted into the bloodstream by the pancreas and acts to reduce blood sugar levels when they become too high – after a meal, for example. In people with diabetes however, this process is disrupted due to either insufficient insulin secretion, or bodily insulin resistance.
Today, insulin itself is used as a medication to help people manage their diabetes, but this hasn’t always been the case. As therapeutic insulin enters its one hundredth year, we’re going to run through some of the key moments that lead to its discovery.
In the mid 19th century, Paul Langerhans discovered small patches of pancreatic tissue, which were observed to secrete a variety of unidentified hormones. These patches were aptly named ‘Islet’s of Langerhans’, though their function remained elusive.
Twenty years later, while experimenting on dogs, Oscar Minkowski and Joseph von Mering were the first to uncover the link between the pancreas and blood sugar levels. The researchers removed the pancreata (yes, that is the plural of pancreas!) from healthy dogs,, and found that their urine contained abnormal quantities of sugar. Links were immediately considered between this and the unidentified pancreatic hormones discovered by Langerhans.
Edward Albert Sharpey-Shafer, also known as the father of endocrinology, hypothesised that the link between the pancreas and blood sugar levels was controlled by a singular hormone, which he named ‘insulin’.
Just under 100 years ago, Frederick Banting and Charles Best removed canine pancreata and found a method of isolating the hormone that they believed was the proposed ‘insulin’ hormone. This substance was then injected back into the dogs, which successfully reduced their blood sugar levels, keeping them alive without a pancreas – something completely unimaginable, previously. Insulin had finally been discovered. Their favourite dog, Marjorie actually stayed alive for 70 days, before dying from an infection caused by the pancreatectomy.
The following year, insulin was administered to humans for the very first time. 14-year-old Leonard Thompson was the first human recipient of insulin, and had his blood sugar levels reduced to near-normal levels. This was a hugely significant moment in modern medicine – prior to this, the diagnosis of type I diabetes was a solid death sentence. Against all odds, Leonard went on to live another 13 years, before eventually passing away from unrelated causes.
Another patient among the first to receive insulin was 5-year-old Theodore Ryder, who was originally given 2-3 months to live following his diagnosis. Theodore went on to live until 1993!
The development of the insulin we know today continued for many years, including Eli Lilly’s commercial release of bovine insulin (1923), the production of recombinant human insulin by Genetech (1978), the introduction of the first insulin pen delivery system by Novo Nordisk (1985), and the introduction of the first ever insulin pump by Medtronic (1992).
As we celebrate World Diabetes Day – 14th November 2020, we’d like to remember these people (and animals) who contributed to the discovery of insulin – a drug that has saved millions upon millions of lives.