Bioenergetics in clinical medicine. XI. Studies on coenzyme Q and diabetes mellitus.

The activity of the succinate dehydrogenase-coenzyme Q10 reductase from 120 diabetic patients was significantly lower (P less than 0.001) and the per cent deficiency was significantly higher (P less than 0.001) than that of the controls. The diabetes of 37 patients was controlled by diet; the enzyme activity was lower (P less than 0.001) and the deficiency was higher (P less than 0.02) than for controls. In decreasing effectiveness, Dymelor, Glyburide, Phenformin and Tolazamide inhibited the COQ10-enzyme, NADH-oxidase. Tolbutamide, Glypizide, and Chlorpropamide were noninhibitory to succinoxidase and NADH-oxidase. Patients receiving Tolazamide and Phenformin showed a higher incidence (P less than 0.001 to P less than 0.05) of COQ10-deficiency than patients controlled by diet or normal controls. Certain diabetic patients controlled by diet may have a deficiency of COQ10 which may be enhanced by the inhibition by certain commonly used antidiabetic drugs of COQ10-enzymes. A deficiency of COQ10 in the pancreas could impair bioenergetics, the generation of ATP, and the biosynthesis of insulin.