title: Effects of mild chronic heat exposure on the concentrations of thiobarbituric acid reactive substances, glutathione, and selenium, and glutathione peroxidase activity in the mouse liver.
abstract: To determine whether mild and chronic heat stress leads to oxidative stress and to differentiate such effects of different exposure periods, we kept male ICR-mice at an ambient temperature of either 35 degrees C or 25 degrees C for 6 hours, 3 days, or 7 days and measured the concentrations of thiobarbituric acid reactive substances (TBARS), glutathione (GSH), selenium (Se), and glutathione peroxidase (GSH-Px) activities in the liver. Since the food consumption of the heat-exposed group was only half that of the control, we prepared pair-fed groups, which were kept at 25 degrees C and whose food consumption were limited to those of the heat-exposed group for the 3-day and the 7-day exposure. TBARS concentrations of the liver was significantly higher in the heat group than the control after the 3-day exposure, while there was no significant difference among the groups after the 7-day exposure. There was no significant difference in GSH concentrations between the heat-exposed group and the control after the 7-day exposure, when the GSH concentration of the pair-fed group was significantly lower than that of the control. Hepatic cytosolic Se GSH-Px activity in the heat group was significantly less than that in the control group after the 6-hour exposure and it tended to be lower in the heat group than that of the control group after the 7-day exposure, while there was no difference in the total GSH-Px activity among the three groups. Our results showed that mild and chronic heat exposure may cause oxidative damage to organisms and that GSH-related anti-oxidative systems would play an important role to defensive reaction.
authors.affiliation: Environmental Health Sciences, Tohoku University Graduate School of Medicine, Sendai, Japan. kasanuma@ehs.med.tohoku.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Kasanuma
authors.forename: C
authors.initials: C
authors.lastname: Watanabe
authors.forename: C Y
authors.initials: CY
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Yin
authors.forename: H
authors.initials: H
authors.lastname: Satoh
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism*; D018882:Heat Stress Disorders; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018384:Oxidative Stress; D012643:Selenium / Q000378:metabolism*; D013858:Thiobarbiturates / Q000378:metabolism*
chemical_list: D013858:Thiobarbiturates; D005979:Glutathione Peroxidase; D005978:Glutathione; D012643:Selenium; C029684:thiobarbituric acid