John James Macleod Nobel Prize in Physiology or Medicine, 1923, jointly with Frederick Banting Date of Birth: 06.09.1876 Country: Great Britain

1. Early Life and Education
2. Research and Career in the United States
3. Discovery of Insulin
4. Nobel Prize and Later Career
5. Personal Life and Legacy

Early Life and Education

John James Rickard Macleod was born in Cluny, near Dunkeld, Perthshire, Scotland, on November 6, 1876, to Jane Guthrie (McWalter) Macleod and Robert Macleod, a clergyman. Macleod received his early education at Aberdeen Grammar School. In 1893, he matriculated at Marischal College, University of Aberdeen, to study medicine. He excelled in his studies and graduated with honors in 1898 with degrees of Bachelor of Medicine and Bachelor of Surgery.

An Anderson Foreign Scholarship enabled Macleod to spend the following year at the Physiological Institute of the University of Leipzig in Germany. He then worked as Assistant Professor of Physiology at the London Hospital Medical School, where two years later he was appointed Lecturer in Biochemistry. During this time, he also received a MacKinnon Research Scholarship from the Royal Society of London.

Research and Career in the United States

In 1903, Macleod co-authored the textbook "Practical Physiology." He then moved to the United States and, despite being only 27 years old, became Professor of Physiology at Western Reserve University (now Case Western Reserve) in Cleveland, Ohio. Two years later, he collaborated with Sir Leonard Hill on the book "Recent Advances in Physiology." He also began his research on carbohydrate metabolism and the disease now known as diabetes mellitus.

Discovery of Insulin

In 1916, British physiologist Edward A. Sharpey-Schafer proposed the name "insuline" for a hypothetical substance in the pancreas with blood sugar-lowering effects (Macleod later changed the term to "insulin"). Although Macleod clearly saw the link between the pancreas and diabetes, he was unable to identify the precise role of the organ in the disease.

In 1918, Macleod was appointed Professor of Physiology at the University of Toronto in Canada. The following year, he was approached by a young Canadian surgeon, Frederick G. Banting, who requested equipment for a research project on diabetes. Banting was particularly interested in extracting insulin from the pancreatic islet cells. In May 1921, Banting and his assistant, Charles Best, embarked on a series of experiments at the University of Toronto, while Macleod was away on vacation in Scotland.

By the time Macleod returned in August, Banting and Best had successfully extracted insulin from the islet tissue of dogs. They had also removed the pancreas in one dog and then injected the islet cell extract into the animal, which was dying of ketoacidosis. The dog recovered, with blood glucose levels returning to normal and glucose disappearing from the urine.

Nobel Prize and Later Career

Macleod and Banting shared the 1923 Nobel Prize in Physiology or Medicine "for the discovery of insulin." Upon learning that Best was not included in the award, Banting threatened to decline the prize but was eventually persuaded not to. He did, however, give half of his award money to Best, publicly acknowledging the latter's contribution to the discovery of insulin. Macleod also later gave a sum of money to Collip.

After receiving the Nobel Prize, Macleod published the book "Insulin and Its Use in Diabetes" and served as President of the Royal Canadian Institute for one year. In 1926, his work "Carbohydrate Metabolism and Insulin" was published, followed two years later by a series of lectures he gave at Princeton University titled "Fuel for Life." He also held the position of Regius Professor of Physiology at the University of Aberdeen, where he later became Dean of the Faculty of Medicine.

Personal Life and Legacy

Macleod married Mary Watson McWalter in 1903, and they had no children. He died on March 16, 1935, from crippling arthritis.

Macleod was a member of the American Physiological Society and the Royal Canadian Institute, a Foreign Member of the Philadelphia College of Physicians, Honorary Fellow of the Royal Academy of Medicine in Rome, Fellow of the Royal Society of Canada, the Royal Society of London, and the Royal College of Physicians. His legacy as a pioneering physiologist and co-discoverer of insulin has had an immeasurable impact on the treatment of diabetes and the lives of millions worldwide.