Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Wood frogs can endure the freezing of up to 65% of their total body water for periods of at least 2 weeks as part of an overall strategy for surviving the harsh temperature, food deprivation and water deprivation conditions that occur during the winter months. During this time, respiration and circulation completely cease and metabolic rates drop precipitously leaving the animal in a dormant state that allows the conservation of energy until environmental conditions improve. In the frozen state, Rana sylvatica accumulate extremely high glucose concentrations (approximately 200 umol/ml blood) as a cryoprotectant (1). The glucose is derived from liver glycogen through the action of phosphorylase a on glycogen stores (1). Glucose export from the liver is aided by inhibition of phosphofructokinase (PFK; 2,3) to severely restrict glycolysis preventing glucose utilization by the liver. In order to maintain high extracellular glucose concentrations, glucose utilization pathways in all other organs must also be down-regulated. In liver, these cellular controls have been identified and include hormone-triggered control of fructose 2,6-bisphosphate concentrations (3). However, much less is known about glycolytic regulation during freezing by other tissues. The present poster addresses this question in erythrocytes.

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