The peculiarities of protein, lipid metabolism and sexual hormones concentration in adult male rats due to the impact of emotional stress in period of milk feeding have been studied. It has been revealed that stress in this period functions according to imprinting type that result in feminization of the parameters of sexual hormones contents and metabolic processes, which shows gender features in normal animals and their parameters similar to intact females. The concentrations of testosterone (6,78±0,44 nmol/L), triglycerides (2,0±0,04 mmol/L), total protein (150,30±3,8 mg/mL) in serum of stressed males were similar to intact females – 5,6±0,30 nmol/L; 2,1±0,1 mmol/L; 160,91±5,1 mg/mL respectively. The liver concentration of testosterone (1,06±0,01 nmol/L), total protein (261,30±6,33 mg/mL), activity of alanineaminotransferase (1,08±0,05 mmol/hour per mg protein) of stressed male also did not differ from those of females indicators – 1,09±0,05 nmol/L; 253,73±5,15 mg/mL; 1,05±0,03 mmol/hour per mg protein, respectively. The changes of arginine amino acid distribution in blood and liver as well as significant increase of nitric oxide level. Thus, in intact males concentration of nitric oxide in the serum was 0,14±0,01 mmol/L, in stressed males – 0,61±0,01 mmol/L. Thus, in adult male rats, due to the action of stress in the during dairy feeding, shifting the concent of the sex hormones, substantial violation of protein and lipid metabolism. Also different from phesiological content of arginine amino acid, which are antyoxidation, and increase in the concentration of nitric oxide (free radical), which in turn is a sign of chronic oxidative stress and damage to the foundation of vascular tone, which may be the initiating step in the the pathogenesis of male infertility.