MECHANISM OF CITRININ-INDUCED DYSFUNCTION OF MITOCHONDRIA .1. EFFECTS ON RESPIRATION, ENZYME-ACTIVITIES AND MEMBRANE-POTENTIAL OF RENAL CORTICAL MITOCHONDRIA

Citrinin depresses the phosphorylation efficiency of rat renal cortical mitochondria, as inferred from the decrease of the respiratory control coefficient (RC) and ADP/O ratios. The transmembrane potential (DELTA-psi) developed by energized mitochondria and the depolarization upon ADP addition are also decreased. Citrinin (1.0 mM) inhibits almost all enzymes linked to the respiratory chain and increases the activity of succinate cytochrome c reductase and succinate oxidase (coupled). Malate and glutamate dehydrogenases are also inhibited. The inhibitory action of citrinin on phosphorylation efficiency could be related to the following findings: the effect on complex I; the action on the ATP synthetase complex; the partial inhibition of the transmembrane potential.