Age-Related Effects of Heat Stress on Protective Enzymes for Peroxides and Microsomal Monooxygenase in Rat Liver

Abstract

To evaluate the age-related response of essential cell fiuctions against peroxidative damage in hyperthermia, we s the bi response to heat stress in both young a aged rats.Passive hyperhermiawas immediately observed in ratsafter ex e to tenvionments. In aged rats, the rctal temperature mntaned thermal homeostais and increased to the same degee as in young rats. in these aged animals, the daage from heat stres was more serious tha '

Age-related changes of antioxidant enzyme activities, glutathione status and lipid peroxidation in rat erythrocytes after heat stress

“…In animals and humans, some physiological and biochemical mechanisms of adaptation against increased temperatures are strengthened (Ando et al, 1997). In our study, all animals in the heat stressed groups exhibited increased rectal temperature and decreased body weight as responses to attain thermal homeostasis to a hot environment.…”

“…Studies on the effects of heat stress on oxidative status in rat erythrocytes are lacking, and very little information is available on the age-dependent effects of heat stress. No data concerning age-related effects of heat stress on the antioxidant enzyme activities in rat erythrocytes have been reported, but there are many reports about changes in these activities in the other rat tissues (Hall et al, 2000;Kasanuma et al, 1998;Ando et al, 1997). Therefore, the aim of the present study was to determine the age-related effects of heat stress on antioxidant enzyme activities, glutathione status, redox index, and lipid peroxidation in rat erythrocytes.…”

“…Several studies have suggested that heat exposure could result in oxidative stress, which in turn can lead to cytotoxicity (Lord-Fontaine and Averill-Bates, 2002;Bernabucci et al, 2002). In animals and humans, some physiological and biochemical adaptations could occur to protect essential cell functions against heat stress and to permit a rapid recovery from moderate hyperthermic damage (Ando et al, 1997). The biological effects of ROS are controlled in vivo by a wide spectrum of enzymatic and non-enzymatic defense mechanisms.…”

“…From the viewpoint of environmental health, the harmful effects of hyperthermia on organisms have become a matter of concern. Heat stress increases oxygen radicals, possibly by the disruption of the electron transport assemblies of the membrane (Ando et al, 1997). Heat-induced reactive oxygen species (ROS) formation may be an additional factor that provides molecular changes in DNA, proteins, lipids and other biological molecules which contribute to senescense (Bruskov et al, 2002).…”

The effect of heat stress on the induced hepatic drug metabolizing system in rats

“…Further, coagulation factors known to be produced in the liver (II, VII, IX, X, XIII, and antithrombin III) were all decreased due to reduced hepatic protein synthesis (21). In addition, both mitochondria and endoplasmic reticulum of hepatic cells showed serious distortion in shape as a result of hyperthermia in aged rats (22) . It is possible that some or all of the above changes in the liver may have participated in causingthe observed decreases in hepatic drug metabolic enzymes in the induced animal model.…”