Effect of alloxan on phosphate transport in isolated mouse liver mitochondria.

The swelling technique was used to study the transport of inorganic phosphate (Pi) in isolated mitochondria from mouse liver. Mitochondria preincubated with alloxan exhibited an early inhibition of Pi uptake, which was dependent both upon the concentration of alloxan and the duration of the reaction with alloxan. No significant inhibition was found with 1 mM alloxan, whereas 10 mM alloxan caused approximately 50 percent inhibition. Maximum inhibition was observed at 2 min with 10 mM alloxan, and at 10 min with 2.5 mM alloxan. Alloxan did not significantly affect the swelling of mitochondria preincubated with acetate, indicating that the inhibition by alloxan of Pi uptake is due to an action of the drug on the Pi carrier (Pi/OH-). The findings support our Pi-pH hypothesis for the development of alloxan diabetes.