[4] After qualifying as a medical doctor, Randle returned to the University of Cambridge to undertake a Ph.D. under Professor Frank George Young.

[5] For his doctoral thesis entitled "Studies on the Metabolic Action of Insulin", he was awarded his Ph.D. in 1955 and was immediately appointed Lecturer in Biochemistry at the University.

[6] In 1964 he was appointed founding Professor of Biochemistry at the University of Bristol where he built a strong department which carried out original research into mitochondrial transporters, molecular enzymology, protein structure, and mammalian metabolism.

The Randle Cycle describes how the products of fatty acid oxidation in muscle reduces the use of glucose, allowing individuals to switch between fuels according to their carbohydrate intake and suggests a potential mechanism for the development of hyperglaecemia and type 2 diabetes.

The results were in agreement with the mechanism he described, suggesting that the key factor in the development of diabetes could be the excessive release of fatty acids in muscle tissue.