Glycolysis and energetics in organs of hibernating mice (Zapus hudsonius)

Abstract

Hibernation-induced changes in the concentrations of glycolytic intermediates, creatine phosphate, and adenylates were monitored in brain and skeletal muscle of the meadow jumping mouse, Zapus hudsonius, after both short (24 h) and long (5 – 7 d) periods of hibernation. Levels of hexose phosphates were greatly reduced in both organs after 24 h of hibernation, suggesting strong suppression of carbohydrate catabolism early in hibernation and indicating enzymatic regulation at the level of carbohydrate input into glycolysis. Both organs showed large changes in energy status during hibernation. Creatine phosphate content declined progressively over time to levels in 5 – 7 d hibernating animals that were 50 and 60% of control values in brain and muscle, respectively. Total adenylates and ATP levels also fell sharply during hibernation, but the net effect of changing adenylate levels on energy charge was minimal; energy charge was 0.94 in both organs of control animals and fell to 0.88 –0.90 in hibernating animals. The overall reduction in the pool sizes of phosphagen and adenylates in organs of hibernating animals may be one factor involved in metabolic suppression during hibernation.