Effect of aromatic amines on isolated rat-liver mitochondria.

The effect of some unsubstituted aromatic amines and their oand p-hydroxylated derivatives on isolated rat-liver mito chondria has been studied. The o-hydroxylated amines inhibited oxygen uptake in the presence of nicotinamide adenine dinucleotide-dependent respiratory substrates. Of the other compounds only l-amino-4-naphthol inhibited oxygen uptake. The Buccinate oxidase system was inhibited only by l-amino-2-naphthol and l-amino-4-naphthol. The o-hydroxylated compounds impaired the efficiency of oxidative phosphorylation; the effect of 4-amino3-hydroxybiphenyl was much more evident when a-oxoglutarate was used as respiratory substrate. l-Amino-2-naphthol and l-amino-4-naphthol completely suppressed phosphate esterification. 1,2-Naphthoquinone and 1,4-naphthoquinone impaired the efficiency of oxidative phosphorylation when supported either by /3-hydroxybutyrate or by succinate. o-Aminophenol, 4-amino3-hydroxybiphenyl, and 2-amino-l-naphthol stimulated mitochondrial adenosine triphosphatase in the presence of Mg++; the last two compounds inhibited the dinitrophenol-induced adenosine triphosphatase activity. l-Amino-2-naphthol and l-amino-4-naphthol inhibited adenosine triphosphatase in the presence of Mg"1"1" and Mg"*""*" plus 2,4-dinitrophenol.