[Cytochrome concentration in the liver at different stages of adaptation to cold]

Concentration of cytochroms in the liver of adult male rats has been studied during the acclimation to cold. One group of rats was kept at about 24 degrees, another at 2--4 degrees. After a month of acclimation to cold the cytochroms concentration in the liver increased, whereas the mitochondrial concentration of cytochroms remained unchanged. It is possible to distinguish three steps of cytochroms concentration changes; 1. on the 9th day of acclimation to cold cytochroms concentration increased 1.5--2 times; 2. by the 14th day the cytochroms concentration decreased (to the control level and lower); 3. after about one month of acclimation to cold the cytochroms concentration increased again. In the skeletal muscle it increased on the 14th (but not on the 9th) day.