GLYCOLYSIS AND ENERGETICS IN ORGANS OF HIBERNATING MICE (ZAPUS-HUDSONIUS)

Hibernation-induced changes in the concentrations of glycolytic interm ediates, creatine phosphate, and adenylates were monitored in brain an d skeletal muscle of the meadow jumping mouse, Zapus hudsonius, after both short (24 h) and long (5-7 d) periods of hibernation. Levels of h exose phosphates were greatly reduced in both organs after 24 h of hib ernation, suggesting strong suppression of carbohydrate catabolism ear ly in hibernation and indicating enzymatic regulation at the level of carbohydrate input into glycolysis. Both organs showed large changes i n energy status during hibernation. Creatine phosphate content decline d progressively over time to levels in 5-7 d hibernating animals that were 50 and 60% of control values in brain and muscle, respectively. T otal adenylates and ATP levels also fell sharply during hibernation, b ut the net effect of changing adenylate levels on energy charge was mi nimal; energy charge was 0.94 in both organs of control animals and fe ll to 0.88-0.90 in hibernating animals. The overall reduction in the p ool sizes of phosphagen and adenylates in organs of hibernating animal s may be one factor involved in metabolic suppression during hibernati on.