Serum and muscle tissue ubiquinone levels in healthy subjects.

Ubiquinone, or coenzyme Q, is a mitochondrial component with antioxidant properties. It has been suggested that ubiquinone therapy may have clinical benefits in some diseases with mitochondrial dysfunction and that the antioxidant effects could be useful, for example, in the prevention of atherosclerosis. Based on this clinical interest, guidelines for the interpretation of ubiquinone analyses are needed. Our results show that serum and muscle ubiquinone levels vary over a wide range in healthy subjects. The serum levels of ubiquinone depend mostly on the amount of ubiquinone-containing lipoproteins in circulation. Physical activity markedly affects muscle tissue levels of ubiquinone. We observed that serum and muscle tissue ubiquinone levels do not correlate with each other, suggesting that they are independently regulated.