HIBERNATION METABOLISM OF MAMALIA
(MARMOTA MENZBERI
KASCHK) AND REPTILES (TESTUDO HORSFIELDI GRAY)Suriye GIBAROVA
Uludag University, Science Faculty, Department o f Biology, 16059, Gorukle, BURSA, TURKEY
ABSTRACT
It has been revealed that, upon hypnosis resulting from the winter hibernation, the content of glucose in the blood of mamals (Marmota menzberi Kaschk.) and reptiles( Testudo horsfieldi Gray) has decreased whereas the components of the lipid exchange and the activity of the enzyme alanin and aspartat transaminase have increased, the changes observed being more pronounced in the tortoise than in marmote.
On a level of the intact organism in vitro, over the 30 fold and 100 fold decrease of gas oxygen exchange takes place in marmots and tortoises, respectively upon the body temperature decreases as low as 4-5°C as a result of winter hibernation.
At a mitochondrial level, a decrease in the bioenergetic parameters by 4-6 times with a prevailing inhibition of succinate oxidation was recorded in marmots and by 3 times in tortoises in the state of hypobiosis, which witnesses deep restructuring of the enzymatic metabolic characteristics of the tissue energetics under these conditions. More significant inhibition of the respiratory activity in the mitochondria of the liver, kidney and heart against the other organs was reported in ground squirrel when in the state of natural winter sleeping.
Upon the temperature drop in vitro by 37,25,16°C the respiratory activity of the liver mitochondria of active rodents was recorded to decrease to a significantly smaller degrees ( by 4 times ) than in those of the reptiles ( by 12 times ), thus witnessing a smaller temperature dependence of the subcellular energetics of the warm blooded animals and the necessity of functioning of special mechanism decreasing mitochondrial respiration in this group as compared with the cold blooded animals while in hypobiosis.
INTRODUCTION
Adaptation of animals various living conditionals on earth also leads to the variations and differences in their behaviours. Actograms of animals shows that they do not get a long period of sleep but rather they have a short sleeping period followed by an active state under normal conditions. However, metabolisms of certain animals slows down, body temperatures and blood circulation's are also decreases to a minimal levels during their dormant state. Hibernation period in these animals begins with the significant decrease in their body temperature. The large decrease in the body functions and metabolic activities distinguishes the hibernation period from winter sleep period.
Certain specials of animals gets into relatively dormant winter sleep periods under abnormal environmental conditions. But during this calm resting period, body temperature, respiration rate and blood pressure stays at normal levels. Animals use their depot fats during this sleeping period. Analysis of the biochemical mechanisms of winter sleep period may provide further information on the control of metabolism in animals (1).
MATERIAL AND METHOD
Marmota menzbieri Kaschk. , Citellus fulvus Light, Testudo horsfieldi Gray and Agama sanguinolenta Nikolsky was used as model organisms in this research. Marmota menzbieri
Kaschk lives in the mountainous regions of central Asia. Their active periods extend from April to June. Their winter sleep period takes 6 months. Citellus fulvus Light also lives in the savannas of central Asia. But their active period is only from April to May. However, these animals go to summer sleep period and then they directly go to winter sleep period without any interference. Testudo horsfieldi Gray also lives at the savannas of central Asia like Citellus
fulvus Light and it shows similar type of activity period.
All animals used in this study are maintained at the controlled vivariums during the study periods.
The blood parameters of Marmota menzbieri Kaschk and Testudo horsfieldi Gray were determined with " £ehoslavakilochom" test kits. Cells organelles are isolated with Hogeboom- Schneider methods as described. Mitochondrial energetics were determined with Chance- Williams method. Protein concentrations of mitochondria extracts were determined with standard Lowry assays. Statistical analyses of the results were done with Student-Fischer test.
DISCUSSION
In this study, the respiration rates of isolated liver, hearth, kidney, muscle, fat and brain tissues of Squirrels were determined. Dramatic decreases in the metabolic functions of liver, hearth and kidney were determined in animals. But the metabolic activities of fat and brain tissues remained at same levels. Metabolic parameters in these tissues of animals that goes through the winter sleep period showed significant differences than the normal values. Blood parameters of Marmota and Testudos were compared during their winter sleep periods. Results of these experiments also indicated the same pattern of decrease in blood parameter of Testudos were much higher than the others. mitochondrial oxidation capacity was also determined in Marmota's using in-vitro assays as described. Results indicated that oxidation rate in Testudos are higher than Marmota's (2,3,4,5).
RESULTS
1. Blood parameters of animals that gets in to winter sleep period was analysed. It was shown that, while the blood glucose level decreases, the amounts of lipids and alanine-aspartate transaminases in Marmots and Testudos the winter sleep period. The rate of increase was much higher in Testudos.
2. In-vivo studies showed that the decrease of body temperature down to 4-6 results with the decrease of oxygen consumption, being 30 folds in Marmot's and 100 folds in Testudos. 3. In-vitro studies indicated that Succinate, Pyruvate and Malate levels decreases 2-5 folds in
liver mitochondria of Marmotes and Testudos.
4. Mitochondrial functions of Citellus fulvus Light were also analysed. Results indicated that mitochondrial functions in liver, kidney and heart tissue is very low, but the metabolic activities in fat tissue were very high.
5. In-vitro analysis of mitochondrial functions in Marmots and Testudos at 37,25, and 160 C resulted with 5-fold decrease in Marmot's and 10 fold in Testudos (6).
REFERENCES
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4. Wang L.C.H. Hibernation and endocrines/ In : Hibernation and tospor in mammals and birds. Aced.Press.N.4.Lond.1982.p. 206-236.
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6. Gibarova S., Hibernation Metabolism of Mammalia ( Marmota menzberi Kaschk.) And Reptiles (Testudo horsfieldi Gray).Ph.D. thesis, Taskent 1996. 119 pp.
