365: Chemistry for Life
DAY 11

The Discovery of Insulin

January 1922, the first successful treatment of diabetes with insulin, co-discovered by chemist Charles Best.

A healthy breakfast alongside diabetic testing equipment

Credit: iStock

Before the discovery of insulin, diabetes was a feared disease that most certainly led to death. Doctors knew that sugar worsened the condition of diabetic patients and that the most effective treatment was to put the patients on very strict diets where sugar intake was kept to a minimum. At best, this treatment could buy patients a few extra years, but it never saved them. In some cases, the harsh diets even caused patients to die of starvation.

During the nineteenth century, observations of patients who died of diabetes often showed that the pancreas was damaged. In 1869, a German medical student, Paul Langerhans, found that within the pancreatic tissue that produces digestive juices there were clusters of cells whose function was unknown. Some of these cells were eventually shown to be the insulin-producing beta cells. Later, in honor of the person who discovered them, the cell clusters were named the islets of Langerhans.

In 1889 in Germany, physiologist Oskar Minkowski and physician Joseph von Mering, showed that if the pancreas was removed from a dog, the animal got diabetes. But if the duct through which the pancreatic juices flow to the intestine was ligated – surgically tied off so the juices couldn’t reach the intestine – the dog developed minor digestive problems but no diabetes. So it seemed that the pancreas must have at least two functions:

  • To produce digestive juices
  • To produce a substance that regulates the sugar glucose

This hypothetical internal secretion was the key. If a substance could actually be isolated, the mystery of diabetes would be solved. Progress, however, was slow.

Visit the official web site of the Nobel Foundation to learn more about the discovery of insulin.

Excerpted with permission, www.nobelprize.org