EFFECT OF HYPERTHERMIA ON GLUTATHIONE-PEROXIDASE AND LIPID PEROXIDATIVE DAMAGE IN LIVER

1. Significant lipid peroxidation occurred both in rat and guinea pig liver in passive hyperthermia caused by a hot environment. In guinea p ig, lipid peroxidation was greatly induced not only in liver homogenat e but also in intracellular structures, such as mitochondria and micro somes. 2. In rat, hepatic cytosolic selenium glutathione peroxidase ac tivities were greatly induced in hyperthermia, while hepatic cytosolic glutathione peroxidase activities in guinea pig were not affected in hyperthermia. 3. In both animals, hepatic cytosolic glutathione S-tran sferase, cytosolic superoxide dismutase, and catalase activities were not affected. 4. Since the peroxidation of lipids in biological membra nes is a destructive phenomenon and is associated with a variety of ce llular damage, hyperthermia greatly developed hypertrophy and vacuoliz ed degeneration in hepatic cells. 5. In guinea pig, the activities of hepatic mitochondrial electron transport system, such as cytochrome c oxidase and cytochrome c reductase system were simultaneously inhibite d in hyperthermia. 6. On the other hand, hepatic microsomal electron t ransport system, such as cytochrome P450 and aminopyrine N-demethylase activities were not seriously affected by hyperthermia. 7. In nuclei and mitochondria, 90-kDa heat shock induced proteins markedly expresse d in fiver. 8. Since hyperthermia greatly induces lipid peroxidation i n liver, heat stress may have a potential impact on peroxidative damag e in humans and animals.