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 pig, lipid peroxidation was greatly induced not only in liver homogenate but also in intracellular structures, such as mitochondria and microsomes. 2. In rat, hepatic cytosolic selenium glutathione peroxidase activities 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-transferase, cytosolic superoxide dismutase, and catalase activities were not affected. 4. Since the peroxidation of lipids in biological membranes is a destructive phenomenon and is associated with a variety of cellular damage, hyperthermia greatly developed hypertrophy and vacuolized 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 inhibited in hyperthermia. 6. On the other hand, hepatic microsomal electron transport 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 expressed in fiver. 8. Since hyperthermia greatly induces lipid peroxidation in liver, heat stress may have a potential impact on peroxidative damage in humans and animals.