Marked over expression of uncoupling protein-2 in beta cells exerts minor effects on mitochondrial metabolism

► The impact of UCP-2 over expression on mitochondrial function is controversial. ► We tested mitochondrial functions at defined levels of overexpression. ► We find minor increases of fatty acid oxidation and uncoupling. ► Effects were seen only at high level (fourfold) of over expression. ► Hence it is doubtful whether these effects are of importance in diabetes.