Occurrence of Newly Synthesized Monoamine Oxidase in Subcellular Fractions of the Rat Liver

The rates of return of monoamine oxidase activity in rat liver mitochondrial and microsomal fractions following inhibition by pargyline or iproniazid were investigated. When these irreversible inhibitors were administered at dosages which produced 100% inhibition, the rate of return of enzyme activity was found to be more rapid in the microsomal fractions than in the mitochondrial fractions. In addition, it was observed that emetine or chloramphenicol inhibited the synthesis of monoamine oxidase but inhibition was not noted until 48hr. after administration of these compounds.