Anaerobic glycolysis in cardiac tissue from a hibernator and non-hibernator as effected by temperature and hypoxia

1. 1. Rates of anaerobic glycolysis were measured in cardiac tissue from hypoxic ground squirrels ( Citellus tridecemlineatus) and albino rats. 2. 2. After hypoxia glycolysis increased significantly in both species at 38°C. At temperatures from 5 to 38°C glycolytic rates were significantly higher in tissue from control active (summer) or hibernating (winter) ground squirrels as compared to control rats. Glycolysis increased significantly during hibernation. 3. 3. At low temperatures energies of activation ( E A ) for glycolysis in rat tissue were higher than those in ground squirrel tissue. 4. 4. Interspecific differences in glycolytic rates support the hypothesis that the hibernator is better adapted to hypoxia and hypothermia than the homeotherm.