Activity of some respiratory enzymes and cytochrome contents in rat hepatic mitochondria following aflatoxin B 1 administration

Abstract

Effects of aflatoxin B 1 (AFB 1) administration (7 mg/kg body weight i.p.) on rat hepatic mitochondrial respiratory components have been examined. Succinoxidase and cytochrome oxidase activities were decreased in liver mitochondria isolated from rats 12–24 h after AFB 1 treatment. Both enzyme activities returned to normal levels after 48 h. Glutamate dehydrogenase and β-hydroxybutyrate dehydrogenase activities did not show any alterations up to 24 h and thereafter increased at 48–72 h. Succinate dehydrogenase activity was impaired by 41% at 12 h and thereafter was found to be normal. The intramitochondrial cytochrome b content declined at 24–72 h, whereas cytochrome aa 3 content was decreased maximally at 72 h after AFB 1 administration. These observations on mitochondrial enzyme activities and cytochrome contents correlate well with our earlier observations made on hepatic mitochondrial respiratory rates after AFB 1 treatment. The impairment of respiratory functions possibly results from membrane damage and selective modification of gene expression in mitochondria imparted by AFB 1.