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KMID : 0351619640050010181
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Kyungpook Medical Journal
1964 Volume.5 No. 1 p.181 ~ p.193
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Effects of Acute and Chronic Cold Exposure on some Metabolic Activities of Rat Liver, Brain and Heart
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Abstract
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This study was aimed to elucidate 1) the particular pattern of some metabolic activities in some vital organ, i, e, , brain, liver and heart during the period of cold exposure; acute form, and chronic form, 2) interrelationship between metabolic activities in different tissues, 3) mechanism by which the animal can adapt to the cold environment.
Rats were exposed to the cold environment of 0 (2 )C for various lengths of time, and the effects of cold exposure on the tissue respiration, anaerobic glycolysis and pattern of nucleic acid contents in liver, brain and heart were studied at 1, 3, 6, 12, and 24 hour interval for the acute form of cold exposure and at 1, 2, 5, 10, 15, and 20 day interval for the chronic form.
The results obtained are summarized as follows:
1. No significant change was observed in the anaerobic glycolysis and the nucleic acid contents (RNF- DNA) of the liver and brain tissue when rats were acutely exposed in cold environment.
2. The oxygen consumption rate of the brain tissue showed a marked increase at the 3rd hour of cold exposure and a noticeable decrease at the 24 hours of the cold exposure. On the other hand, an increased rate of oxygen uptake was noted in the liver tissue at the 12th hour of cold exposure and followed by a progressive decrease to the normal level at the 24th hour of cold exposure.
3. The oxygen consumption rate and RNA contents of liver and brain tissue showed the lowest value at the 2nd day of cold exposure and a highly significant increase was noted at the 5th day of cold exposure and thereafter decreased again to the normal value up to the 10th day of cold exposure.
4. The anaerobic glycolysis in liver tissue decreased gradually throughout the period of cold exposure, whereas that in brain tissue showed peak values at the 2nd and 5th days followed by a decrease to the control level on the 10th day of cold exposure.
5. The similarity betwecn the patterns of changes in oxidative metabolism of brain and liverand changes in glycolytic activity in brain and RI\fA contens changed in brain and liver during the period of cold exposure, suggests the existence. of a close relationship in those different mei;abolic activities between liver and brain tissue.
6,. No direct relation was noted between the change of anaerobic glycolysis, and that of the oxidative metabolism and the nucleic acid contents, in the liver tissue.
7. The oxygen consumption, anaerobic glycolysi:~ and nucleic acid contents in the cardiac muscle, and the DNA contents in all the tissues studied did not show any significant change throughout the entire period of experiments both in acute; and chronic form of cold exposure.
8. The results indicate that a tendency of adaptation to cold enviroment was generally sct in on or around the 10th day of cold exposure.
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