Quick Facts
In full:
John James Rickard Macleod
Born:
Sept. 6, 1876, Cluny, near Dunkeld, Perth, Scot.
Died:
March 16, 1935, Aberdeen (aged 58)
Awards And Honors:
Nobel Prize (1923)
Subjects Of Study:
carbohydrate
insulin
Britannica AI Icon
Adding us as a Preferred Source tells Google you trust our content, so our articles show up more often in your Google Search, Discover feed, and AI Overviews.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

J.J.R. Macleod

Scottish physiologist
Also known as: John James Rickard MacLeod

J.J.R. Macleod (born Sept. 6, 1876, Cluny, near Dunkeld, Perth, Scot.—died March 16, 1935, Aberdeen) was a Scottish physiologist noted as a teacher and for his work on carbohydrate metabolism. Together with Sir Frederick Banting, with whom he shared the Nobel Prize for Physiology or Medicine in 1923, and Charles H. Best, he achieved renown as one of the discoverers of insulin.

Macleod held posts in physiology and biochemistry at the London Hospital (1899–1902) and as professor of physiology at Western Reserve University, Cleveland, Ohio, U.S. (1903–18). In 1918 he joined the University of Toronto, Ont., Can., as associate dean of medicine and subsequently became director of its physiological laboratory. It was in this laboratory that Banting and Best began investigating the secretions of the pancreas and eventually succeeded in isolating and preparing insulin in 1921. Macleod subsequently was made dean of the faculty of medicine.

His publications include Practical Physiology (1902) and Physiology and Biochemistry in Modern Medicine (1918).

Michael Faraday (L) English physicist and chemist (electromagnetism) and John Frederic Daniell (R) British chemist and meteorologist who invented the Daniell cell.
Britannica Quiz
Faces of Science
This article was most recently revised and updated by Encyclopaedia Britannica.
Discover the fascinating events that shaped the world, straight from our editors.
By clicking “Sign Up”, you consent to the Britannica Privacy Policy and Terms of Use.