Resistance of Hepatic Lysosomes, Mitochondria and Microsomes of Protoporphyrin-Administered Rats to Peroxidative Damage

Abstract

Antioxidative inhibition by protoporphyrin (PP) of peroxidative damage in lysosomes, mitochondria and microsomes of rat liver was investigated at 24h after an intravenous administration of PP. Using a lysosome-containing (3500×g) fraction, the release of lysosomal marker enzymes, acid phosphatase and aryl sulfatase, from lysosome which had been stimulated by L-ascorbic acid (AsA), was decreased dose-dependently, as was the inhibition of lipid peroxidation by PP in the fraction. Swelling of mitochondria induced by Fe²⁺ and AsA was also inhibited in the PP-injected rat. In microsomes, lipid peroxidation stimulated by AsA caused a decrease in activity of a microsomal marker enzyme, glucose 6-phosphatase, and in P450 content. The extent of the decrease by AsA, both in activity and content, was diminished in PP-administered rat liver microsomes. These results indicate that PP protects those subcellular fractions from deterioration by lipid peroxidation.