Effect of sodium selenite on guinea-pig cardiac isolated mitochondria

The pre-incubation with sodium selenite reduces the respiratory index in guinea-pig cardiac mitochondria when alpha-ketoglutarate and glutamate are used as substrates. This decrease is dose-dependent. On the other hand, no modification in respiratory index is measured with malate or malate plus pyruvate. The effect on sodium selenite is prevented by CoA administration. Moreover, 25 microM sodium selenite reduces the Km and Vmax of alpha-ketoglutarate dehydrogenase measured at steady-state with variable amount of CoA.