<p>We have previously demonstrated multidirectional changes in trypsin activity and some serum biochemical parameters in rats under conditions of water and food deprivation with following satiation. In the present study, administration of soybean trypsin inhibitor (STI) to animals subjected to water and food deprivation caused a moderate decrease in trypsin activity and an increase in the serum concentration of total protein, which attested to deceleration of protein metabolism. Significant changes in the content of cholesterol and triglycerides against the background of STI administration were also found indicating intensification of lipid and energy metabolism. These findings suggest that STI prevents disturbances of metabolic processes in the body under conditions of water and food deprivation. However, the peculiarities of STI influence on metabolic processes require further study.</p>