Hibernation-hypothermia and metabolism in hedgehogs. Changes in some organic components.

1. Biochemical levels of certain carbohydrates, lipids and proteins were determined in plasma, liver and brain of the oriental hedgehog and compared in active, hypothermic and awake animals. 2. Lipid reserves exhibited significant increase in autumn before the onset of hibernation. This was bound up with the predisposition of the animal to hibernate. 3. During hypothermia, glucose levels, lipid reserves and tissue protein content significantly declined, in contrast to tissue glycogen which remarkably increased. 4. This indicated that glycogenolysis was impaired while gluconeogenesis from lipids and proteins presented the primary source of energy necessary for tissue requirements. 5. During arousal, the marked elevation in plasma glucose concomitant with the drop in tissue glycogen, lipids and proteins indicated that glycogenolysis as well as gluconeogenesis participated in glucose production necessary for the thermogenesis required during wakefulness. 6. Our data suggested that the accumulation of brain glycogen during winter may directly initiate arousal. 7. The nature of the biochemical changes that occurred throughout the hibernation cycle implies that metabolism in hedgehogs is influenced by dynamically balanced control mechanisms operating within a wide range of temperatures.