The Internal Secretion of the Pancreas

Summary

'The Internal Secretion of the Pancreas' is the first scientific paper describing the work at the University of Toronto that led to insulin. Frederick Banting and Charles Best presented their results to a physiological society in Toronto in late 1921, and the paper was published in the Journal of Laboratory and Clinical Medicine in February 1922. Diabetes mellitus was then a fatal disease for most children and young adults who developed it. Patients wasted away despite near-starvation diets. Scientists knew that removing the pancreas from a dog caused diabetes and suspected that small clusters of cells in the pancreas, the islets of Langerhans, produced a substance that controlled blood sugar. Attempts to extract it had failed, perhaps because digestive enzymes from the rest of the pancreas destroyed it. Banting's idea was to tie off the pancreatic ducts of dogs so that the cells producing digestive juices would waste away while the islets survived. In the summer of 1921, working in the laboratory of Professor J. J. R. Macleod, Banting and Best prepared extracts from such degenerated pancreases and injected them into dogs whose pancreases had been removed. The paper reports that the extracts lowered blood sugar and reduced the sugar in the urine, and that the dogs' condition improved. They called the active substance 'isletin'. They later found that extracts of whole fetal calf pancreas also worked. The paper is a careful laboratory report, with charts of blood sugar after injections. It was quickly followed by a second paper, in March 1922, describing the first treatment of human patients, including the fourteen-year-old Leonard Thompson, with a purer extract prepared by James Collip. The substance, renamed insulin, was being produced commercially within a year. The discovery transformed diabetes from a death sentence into a manageable condition and won Banting and Macleod the Nobel Prize in 1923.

Plot or Argument

• Background

  Earlier experiments linked the pancreas to diabetes; attempts to extract the islet secretion had failed.

• Method

  Ligating the pancreatic ducts of dogs to cause degeneration of the digestive cells, then extracting the remaining tissue.

• Experiments

  Injecting the extract into depancreatized diabetic dogs and measuring blood and urine sugar.

• Results

  The extract consistently lowered blood sugar and improved the dogs' condition.

• Sequel

  Clinical trials in January 1922 and purification by Collip led to insulin treatment.

Lessons

• An idea tested

  Banting's idea came from reading a medical article late at night. Turning it into a result took a summer of hard laboratory work.

  • What was Banting's idea for isolating the internal secretion?
  • Why did earlier attempts fail?

• Teamwork and credit

  Banting, Best, Macleod and Collip each contributed, and arguments over credit were bitter. Discoveries rarely belong to one person.

  • What did each member of the team contribute?
  • Why did Banting share his Nobel Prize money with Best?

• Animals in research

  The work depended on experiments on dogs, many of which died. Medical progress raises questions about our duties to animals.

  • How should we weigh animal suffering against human benefit?
  • What responsibilities do researchers have toward laboratory animals?

• For the Christian reader

  The discoverers sold the patent to the University of Toronto for a token sum so that insulin could be made widely. Christians can see in this a picture of knowledge used for the good of others, and in the healing of dying children an echo of Christ's compassion.

  • Why might the decision about the patent matter morally?
  • How does the story of insulin show gifts used for others?

Context

By 1920 diabetes was understood to involve the pancreas, but there was no effective treatment beyond strict diets. Researchers in Germany, Romania and the United States had attempted pancreatic extracts with limited success.

Composition

Banting and Best worked through the summer and autumn of 1921 in Toronto. They reported their results to the Physiological Journal Club in November and to the American Physiological Society in December 1921; the paper appeared in the Journal of Laboratory and Clinical Medicine, volume 7, in February 1922.

Reception

Within a year Eli Lilly and Company and Connaught Laboratories were producing insulin. The 1923 Nobel Prize went to Banting and Macleod, who shared their money with Best and Collip. Controversy over credit continued for decades.

Comparisons

• An Introduction to the Study of Experimental Medicine

  Claude Bernard's method of physiological experiment underlies the Toronto work.

• Germ Theory Papers (Pasteur and Lister)

  Another laboratory discovery that transformed medicine.

• Founding Papers of Psychopharmacology: Cade on Lithium (1949), Delay, Deniker and Harl on Chlorpromazine (1952), Kuhn on Imipramine (1957)

  Later papers that introduced effective drugs in another field of medicine.

Quotes

For Students

A reading companion for classical Christian high school students. See the student guide.

Reading Guide

Watch for

• The problem of extracting the islet secretion.
• The duct-ligation method.
• How results are measured.
• The roles of Banting, Best, Macleod and Collip.

Key terms and names

Pancreas

An organ that produces digestive juices and, in its islets, hormones that control blood sugar.

Islets of Langerhans

Clusters of cells in the pancreas that produce insulin.

Diabetes mellitus

A disease in which the body cannot control blood sugar.

Internal secretion

An older term for a hormone released into the blood.

Seminar Questions

1. Comprehension What was Banting's method for obtaining the extract?
2. Comprehension How did the team measure the effect of the extract?
3. Interpretation Why was Collip's purification important?
4. Interpretation Why did disputes over credit arise?
5. Interpretation What made the 1922 results so convincing to physicians who had seen diabetic children waste away?
6. Big Question How should credit for a shared discovery be divided?

Faith Connections

• Mark 5:41–42 (Scripture)

  Jesus raises a young girl; the healing of a dying child.

• 1 Corinthians 12:21 (Scripture)

  Many members, one body: no part of a team can say it does not need the others.

• Francis Bacon, The New Atlantis (Great Conversation)

  A vision of science organized for the relief of human suffering.

Logic and Rhetoric

Central argument: Extracts of pancreatic tissue in which the digestive cells have degenerated contain the internal secretion that lowers blood sugar in diabetic animals.

Rhetorical device: laboratory report. The paper proceeds from method to measured results with charts of blood sugar.

Debate: Resolved: that lifesaving medical discoveries should not be patented for private profit.

Writing Prompts

Essay: Explain how the discovery of insulin depended on several people with different skills.

Comparison with An Introduction to the Study of Experimental Medicine: Compare the Toronto experiments with Claude Bernard's principles of experimental medicine.

Medical Lens

The first report of the Toronto experiments that led to insulin.

• Experiments

  Extracts from degenerated pancreas lower blood sugar in diabetic dogs.

  Pharmacology Poisons

Creative Prompts

• Essay

  Explain how the Toronto team turned an idea into a treatment within a year.

• Fiction

  Tell the story of January 1922 from the point of view of Leonard Thompson's parents.

• Classroom

  Make a timeline of the discovery of insulin from 1889 to 1923.

Further Reading

• The Discovery of Insulin, Michael Bliss

• Breakthrough: Elizabeth Hughes, the Discovery of Insulin, and the Making of a Medical Miracle, Thea Cooper and Arthur Ainsberg