[Subcellular distribution of porphyrins and anti-lipid peroxidative effect in protoporphyrin-administered rat liver].

The distribution and the anti-lipid peroxidative effects of porphyrins in the hepatic subcellular fractions in rats were studied after intravenous administration of protoporphyrin (PP). PP and/or PP-derived porphyrins were mainly distributed in the membrane-containing fractions of 600 x g-, 10,000 x g- and 100,000 x g-sediment from the liver homogenates of rats receiving a 20 mg/kg dose of PP. The lipid peroxidation induced by L-ascorbic acid in the fractions of 600 x g-, 10,000 x g- and 100,000 x g-sediment from the PP-treated rats was suppressed during 1-168 h, 1-168 h and 12-168 h, respectively, after the PP treatment. The suppression of the peroxidation in the liver mitochondria from the PP-treated rats was further enhanced by the addition of the hepatic cytosol from the PP-treated rats. The extent of the suppression by the addition of the cytosol from the PP-treated rats at 24 h after the PP administration was greater than those at 0 and 168 h after the PP administration. These results indicate that PP and/or PP-derived porphyrins distributed in the liver still exert antioxidative actions and that there might exist some unknown factors enhancing the actions in the hepatic cytosol.