Production of ascorbate and hydroxyl radicals in the liver of LEC rats in relation to hepatitis.

The production of radicals was examined in vitro in liver supernatant prepared from LEC rats of different ages before and after the onset of jaundice. Each liver supernatant was subjected to heat-treatment at 90 degrees C for 10 min to remove heat-labile proteins, and then the production of radicals in the resultant supernatant in the presence of hydrogen peroxide and 5,5'-dimethyl-1-pyrroline oxide (DMPO) was studied by ESR. Two sharp ESR signals that completely decayed with time within 5 min after the addition of hydrogen peroxide were observed for the sample prepared from LEC rats before the onset of jaundice, followed by the appearance of four signals of a hydroxyl radical-DMPO adduct after 5 min. On the other hand, in the supernatant prepared from LEC rats after the onset of jaundice, the former two signals were not observed or observed only marginally, and the signals of the hydroxyl radical-DMPO adduct showed a different pattern of decay from that for the supernatant prepared from LEC rats before the onset of jaundice. With the addition of ascorbic acid to the liver supernatant prepared from LEC rats after the onset of jaundice, the former signals of the ascorbate and hydroxyl radicals reappeared. The present results suggest that ascorbate and hydroxyl radicals are produced in the liver of LEC rats with the onset of jaundice, depending on the relative ratio of ascorbic acid and cuprous ions.