Liver metabolism in cold hypoxia: a comparison of energy metabolism and glycolysis in cold-sensitive and cold-resistant mammals
| Autor: | Thomas A. Churchill, L. C. H. Wang, C. J. Green, S. Simpkin, Bj Fuller, K Cheetham |
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| Rok vydání: | 1994 |
| Předmět: |
Male
medicine.medical_specialty Physiology Acclimatization Adenylate kinase In Vitro Techniques Biology Biochemistry Rats Sprague-Dawley chemistry.chemical_compound Endocrinology Hibernation Internal medicine medicine Animals Glycolysis Energy charge Hypoxia Liver preservation Ecology Evolution Behavior and Systematics Glycogen Sciuridae Rats Cold Temperature Liver chemistry Anaerobic glycolysis Cold sensitivity Animal Science and Zoology medicine.symptom Energy Metabolism Phosphofructokinase |
| Zdroj: | Journal of Comparative Physiology B. 164:396-404 |
| ISSN: | 1432-136X 0174-1578 |
| DOI: | 10.1007/bf00302556 |
| Popis: | The effects of cold hypoxia were examined during a time-course at 2 degrees C on levels of glycolytic metabolites: glycogen, glucose, glucose-1-phosphate, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, phosphoenolpyruvate, pyruvate, lactate and energetics (ATP, ADP, AMP) of livers from rats and columbian ground squirrels. Responses of adenylate pools reflected the energy imbalance created during cold hypoxia in both rat and ground squirrel liver within minutes of organ isolation. In rat, ATP levels and energy charge values for freshly isolated livers were 2.54 mumol.g-1 and 0.70, respectively. Within 5 min of cold hypoxia, ATP levels had dropped well below control values and by 8 h storage, ATP, AMP, and energy charge values were 0.21 mumol.g-1, 2.01 mumol.g-1, and 0.17, respectively. In columbian ground squirrels the patterns of rapid ATP depletion and AMP accumulation were similar to those found in rat. In rat liver, enzymatic regulatory control of glycolysis appeared to be extremely sensitive to the decline in cellular energy levels. After 8 h cold hypoxia levels of fructose-6-phosphate decreased and fructose-1,6-bisphosphate increased, thus reflecting an activation of glycolysis at the regulatory step catalysed by phosphofructokinase fructose-1,6-bisphosphatase. Despite an initial increase in flux through glycolysis over the first 2 min (lactate levels increased 3.7 mumol.g-1), further flux through the pathway was not permitted even though glycolysis was activated at the phosphofructokinase/fructose-1,6-bisphosphatase locus at 8 h, since supplies of phosphorylated substrate glucose-1-phosphate or glucose-6-phosphate remained low throughout the duration of the 24-h period.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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