ABSTRACT
The emotional-painful stress causes a more pronounced decrease in affinity of hemoglobin to oxygen in portal blood compared with mixed blood. This contributes to increased oxygen pressure in hepatocytes and activates free radical processes in liver microsomes. Activation of lipid peroxidation is accompanied by changes in physical properties (microviscosity, polarity) of microsomal membranes. However, the increase in duration of stress treatment changes in the studied parameters become adaptive; this is accompanied by gradual normalization in blood affinity to oxygen, physical properties of membranes and the increase in antioxidant defence. Possible mechanisms of interaction of these systems during adaptation and regulation of free radical oxydation are discussed.