John James Rickard Macleod

John James Rickard Macleod FRS (6 September 1876 – 16 March 1935) was a Scottish physician and physiologist. He was noted as one of the co-discoverers of insulin and awarded the Nobel Prize for this discovery.

Biography
Macleod was born at Clunie, Perthshire, Scotland. He was the son of the Rev. Robert Macleod.

During 1898 he received his medical degree from University of Aberdeen and went to work for a year at the University of Leipzig. During 1899 he was appointed Demonstrator of Physiology at the London Hospital Medical School and in 1902 he was appointed Lecturer in Biochemistry at the school. During 1903 he was appointed Professor of Physiology at, what is now called, Case Western Reserve University at Cleveland, Ohio. During 1918 he was elected Professor of Physiology at the University of Toronto, Canada. In 1928 he returned to the University of Aberdeen as Regius Professor of Physiology, where he remained until his death in 1935. He is buried in Allenvale Cemetery, Aberdeen.

Macleod's main work was on carbohydrate metabolism and his efforts with Frederick Banting and Charles Best in the discovery of insulin used to treat diabetes. For this Banting and Macleod were jointly awarded the Nobel Prize for Medicine in 1923. Macleod was awarded half of the Nobel Prize for the discovery of insulin, even though many people (including Banting) publicly insisted that Macleod's involvement was minimal and Best's work had been essential. However, it was Macleod's research plan and his suggestion to inject intravenous degenerated pancreas into depancreatinized dogs that ultimately led to the successful isolation of insulin. There is currently a controversy regarding the role of Banting and Best in attempting to 'write out' Macleod and his colleague James Collip from the history books. Macleod's receiving the Nobel Prize over Best was controversial at the time (see Nobel Prize controversies). He wrote eleven books, including Recent Advances in Physiology (1905); Diabetes: its Pathological Physiology (1925); and Carbohydrate Metabolism and Insulin. (1926)

Macleod shared his Nobel award money with James Collip.

The auditorium of the Medical Science Building at University of Toronto is named after J.J.R. Macleod. In 2005 Diabetes UK named its offices in London in honour of J.J.R. Macleod.