How Two Scientists and a Team Changed Diabetes Treatment Forever

Frederick G. Banting and John J.R. Macleod won the 1923 Nobel Prize in Physiology or Medicine for discovering insulin, a hormone that regulates blood sugar levels. Before this breakthrough, severe forms of diabetes were often fatal and could only be managed through restrictive diets that extended life for a limited period. The award recognized research conducted at the University of Toronto in the early 1920s, where investigators created pancreatic extracts that lowered blood sugar in diabetic animals and later showed their medical potential in humans.

The Research Team

Banting, a Canadian physician and surgeon, approached Macleod in 1921 with a plan to isolate a substance from the pancreas that could control blood glucose. Macleod, a Scottish-born physiology professor at the University of Toronto, provided laboratory space, guidance, and experimental animals. Banting began the experiments with Charles Best, a medical student who assisted with the work. Later, biochemist James Collip joined the team to purify the extract for clinical use. When Banting and Macleod received the Nobel Prize, Banting shared half of his prize money with Best, and Macleod shared half of his with Collip to acknowledge their vital contributions.

First Human Trials

In January 1922, doctors administered the extract to Leonard Thompson, a 14-year-old boy with severe diabetes at Toronto General Hospital. The first injection caused limited results and an abscess at the site, but after Collip purified the preparation further, a second course of treatment led to a major improvement, a substantial drop in blood sugar, and reduced urinary glucose. Earlier studies by Oskar Minkowski and Joseph von Mering in 1889 had already linked diabetes to the pancreas by showing that removing the organ from dogs produced the disease, pointing researchers toward the islets of Langerhans.

Context

Insulin helps glucose move from the bloodstream into cells to be used for energy or stored for later use, making it essential for individuals with type 1 diabetes whose bodies destroy beta cells. Modern treatments have evolved significantly from the early pancreatic extracts, with various formulations designed to control how fast they work and how long their effects last. World Diabetes Day is observed annually on November 14 to mark the birthday of Frederick Banting, who was born in 1891.