Effects of acclimation and incubation temperature on the glutathione antioxidant system in killifish and RTH-149 cells.
Glutathione (GSH) is an important antioxidant that is involved in a multitude of cellular processes. However, in fish, GSH levels, turnover, and activity of associated enzymes are low when compared to those of mammals. To determine whether temperature influences the GSH antioxidant system in fish, and can explain the differences in GSH between fish and mammals, we examined the effects of acclimation temperature on total GSH (tGSH) levels and apparent half-life (as an estimate of turnover) in a rainbow trout hepatoma cell line (RTH-149), and GSH levels, and glutathione peroxidase (GPx) and reductase (GR) activity in the eurythermal killifish. Increasing incubation temperature decreased half-life and transiently increased levels of tGSH in RTH-149 cells. In killifish, increased acclimation temperature increased tGSH levels in the liver, brain and muscle, and increased hepatic GPx and GR activities. When the relationships between temperature and GSH half-life, levels and enzyme activity were extrapolated to 37 degrees C, temperature could only partially accounted for differences in the GSH antioxidant system in fish compared to mammals. The differences in the GSH antioxidant system between fish and mammals may not be solely due to temperature effects, but also to the increased metabolic cost of endothermy in mammals.
Leggatt
R A
RA
Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4.
Brauner
C J
CJ
Schulte
P M
PM
Iwama
G K
GK
D000064:Acclimatization / Q000502:physiology*; D000818:Animals; D000975:Antioxidants / Q000502:physiology*; D045744:Cell Line, Tumor; D023781:Fundulidae / Q000502:physiology*; D005978:Glutathione / Q000502:physiology*; D019803:Glutathione Disulfide / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D017686:Oncorhynchus mykiss; D013696:Temperature
D000975:Antioxidants; D007770:L-Lactate Dehydrogenase; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D005978:Glutathione; D019803:Glutathione Disulfide