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Rat liver response elicited by long-term cold exposure
G Liverini1, S Iossa, A Barletta
1Department of General and Environmental Physiology, University of Naples, Italy.
Journal of Physiology, Paris
|January 1, 1992
Summary
Long-term cold exposure increases liver and mitochondrial protein mass in rats. However, oxygen consumption in isolated mitochondria and hepatocytes remains unchanged, indicating no increase in hepatic respiration.
Area of Science:
- Physiology
- Mitochondrial Biology
- Environmental Adaptation
Background:
- Cold exposure is a significant environmental stressor.
- Adaptation to cold involves metabolic and physiological changes.
- Mitochondria play a crucial role in cellular energy metabolism.
Purpose of the Study:
- To investigate the effects of long-term cold exposure on hepatic mitochondrial protein mass and respiratory function in rats.
- To determine if increased mitochondrial content correlates with altered oxygen consumption rates.
Main Methods:
- Isolated rat liver mitochondria and hepatocytes were used.
- Mitochondrial protein mass was measured.
- Respiratory rates (State 4 and 3) were assessed using various substrates.
- Oxygen consumption was measured under stimulated conditions.
Main Results:
- Long-term cold exposure significantly increased both liver mass and mitochondrial protein mass.
- No significant variations were observed in the oxygen consumption of isolated mitochondria.
- Hepatocyte respiration rates also showed no change despite increased mitochondrial protein.
Conclusions:
- Long-term cold exposure leads to an increase in the synthesis of mitochondrial proteins in the liver.
- The enhanced mitochondrial protein mass does not translate to a higher overall hepatic oxygen consumption.
- Cold adaptation may involve increased mitochondrial efficiency or altered substrate utilization rather than simply more mitochondria.