Gluconeogenesis in arctic ground squirrels between periods of hibernation.

  title={Gluconeogenesis in arctic ground squirrels between periods of hibernation.},
  author={W. A. Galster and Peter R. Morrison},
  journal={The American journal of physiology},
  volume={228 1},
The hibernation season in the arctic ground squirrel (Citellus undulatus) is broken into 8- to 18- day cycles by short homeothermal periods during which the carboydrate reserves depleted during hibernation are replenished. This study follows a number of metabolities in tissues and body fluids to assess the sources for reconstitution of the glucose reserves: lactate, urea, ammonia, free fatty acid, glycerol, triglyceride, and glucose in plasma; glycogen in liver and muscle; and urea and ammonia… 

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Seasonal activity patterns of glycolytic enzymes in a hibernator, the Arctic ground squirrel Spermophilus parryi

The enzyme activities in skeletal muscle changed in seemingly disparate ways with some enzymes increasing in hibernation, while others decreased, and yet others remained unchanged, in the light of the hibernating habit of the mammal.

Liver energy metabolism during hibernation in the golden-mantled ground squirrel, Spermophilus lateralis

It is shown that total extractable liver [ATP], [ADP], and [ ATP]/[ADP] do not differ among summer normothermic, hibernating, and aroused golden-mantled ground squirrels, Spermophilus lateralis, indicating that metabolism remains well balanced throughout the hibernation cycle.

Metabolic cycles in a circannual hibernator.

This finding provides new data that strongly support the predictions of a long-standing hypothesis that periodic arousals are necessary to restore metabolic homeostasis in ground squirrels.

Nitrogen recycling buffers against ammonia toxicity from skeletal muscle breakdown in hibernating arctic ground squirrels

Evidence of increased myofibrillar (skeletal muscle) protein breakdown and suppressed whole body production of metabolites in vivo throughout deep torpor is shown and the orchestration of metabolic pathways that sustain the provision of essential and non-essential amino acids and prevent ammonia toxicity during hibernation is illustrated.

Metabolic Rate and Prehibernation Fattening in Free-Living Arctic Ground Squirrels

It is found that arctic ground squirrels do not trade off metabolism to facilitate rates of weight gain before hibernation, but they do use energy sparing strategies before hiberration that help maintain peak mass.

Metabolism of hepatocytes from a mammalian hibernator, Spermophilus lateralis

This unique metabolice organization may permit energetic savings by allowing for a reduced Vb2 in deep hibernation, and an elevated VO2 during arousal to support high biosynthesis rates, thereby minimizing arousal durations and their attendant thermogenic demands.

Carbohydrate and torpor duration in hibernating golden-mantled ground squirrels (Citellus lateralis)

It was found that plasma glucose depletion is not the stimulus for arousal in torpid C. lateralis, and plasma glucose and hepatic and skeletal muscle glycogen remain stable during torpor in this species, in marked contrast to the carbohydrate depletion reported for Citellus undulatus.

Regulation of Skeletal Muscle Carbohydrate Metabolism During Mammalian Hibernation

Biochemical controls on carbohydrate metabolism during hibernation and skeletal muscle glycolysis and gluconeogenesis are suppressed during ground squirrel torpor via posttranslational modification and regulation of key enzymes are analyzed.



Cyclic changes in carbohydrate concentrations during hibernation in the arctic ground squirrel.

Plasma glucose, and glycogen in liver and thigh muscle declined steadily during each hibernation period, but glycogen concentrations in kidney, brown fat, and heart did not change, and it is suggested that these declines may directly initiate arousal in this species.

Gluconeogenesis during hibernation and arousal from hibernation.

Protein metabolism in hepatic tissue of hibernating and arousing ground squirrels.

Data suggested an increased protein catabolism during arousal in heparic tissue of hibernating and arousing ground squirrels, compared to hepatic tissue of normothermic animals.

Carbohydrate reserves of wild rodents from different latitudes.

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Energy metabolism in hibernation.

Energy metabolism /chemical energy transfer and transformation/ postulated as fundamental hibernation requirement after comparing interspecific differences

Removal of ammonia by formation of amino acids in rat liver.

Results indicate that the binding of copper to protein in M. trunculu8 haemocyanin involves imidazole groups, although the possibility that other amino acid residues also participate cannot be completely excluded.

An enzymic method for the estimation of glycerol in blood and its use to determine the effect of noradrenaline on the concentration of glycerol in blood.

A sensitive, specific method based on the reduction of DPN in the presence of a partially purified glycerol dehydrogenase prepared from Aerobader aerogenes is described, which finds rabbit plasma to contain 8 to 16 μmoles of Glycerol per 100 ml.