Abstract
The effects of three kinds of hypoglycemic biguanide on the respiration of isolated rat liver mitochondria were studied using Beckman oxygen scensor. The following results were obtained.
1. Both phenformin and buformin were shown to inhibit the respiration of isolated liver mitochondria as reported previously. On the contrary, metformin showed us any influences on the mitochondrial respiration and oxidative phosphorylation.
2. The minimum concentration of phenformin which induced a decrease in respiratory control of liver mitochondria was 50 mg%. That of buformin was 100 mg%.
3. Both phenformin and buformin aparrently decreased DNP release of respiration of liver mitochondria. Metformin showed no effects on the DNP release of respiration.
4. Changing the substrate from succinate to glutamate + malate produced slight change in the effects of phenformin and buformin.
5. The above results, demonstrated that neither phenformin nor buformin inhibit oxidative phosphorylation of liver mitochondria, when administered orally in the nomall dose.
But, there is a small possibility that when these drugs are orally administered in large dose, they can give influence the metabolism of liver mitochondria to a certain extent.
