High Energy Phosphates During Hibernation and Arousal in the Ground Squirrel

Abstract

Biochemical levels of inorganic phosphate, adenosine triphosphate, phosphocreatine and glycogen were determined on cardiac muscle, skeletal muscle and liver samples from hibernated 13-striped ground squirrels and those allowed to awaken for intervals of 7.5, 15 and 30 minutes. Cardiac muscle glycogen increases during hibernation apparently at the expense of skeletal muscle and liver glycogen. Glycolysis occurs in these tissues during early arousal, followed later by glycogenesis. Adenosine triphosphate is maintained in both cardiac and skeletal muscle during hibernation and is used as an energy source during arousal. It appears that glycolysis is important in resynthesizing phosphocreatine. From this study of periods of relatively low and high metabolic demands we conclude that phosphocreatine is a ‘transport’ form of high-energy phosphate forming adenosine triphosphate from the phosphate pool when and where needed in the cycle of intermediary metabolism.