[Effect of adaptation to cold and moderate cooling on respiration and oxidative phosphorylation in the muscle mitochondria of albino rats].

In rats, exposed to cooling at 2 degrees within 2 hrs, total gas exchange and the respiratory activity of sceletal muscles mitochondria were studied. The adapted rats, which were kept at 5-7 degrees within 13-17 days, were compared with unadapted animals (kept at 18 degrees). In the group of adapted rats cooling caused the increase in the total O2 utilization by 105% with increased free oxidation in mitochondria and the distinct decrease in P/O ratio. Cooling of unadapted rats was accompanied by the increase in O2 utilization by 85% without any marked alteration in P/O ratio in sceletal muscles mitochondria. The body temperature was not altered.