Background. Serotonin, which exhibits rhythmic secretion profile, is sensitive to increases and decreases in the day length and can influence other endocrine functions related to reproduction. Males living in polar regions could have several specific characteristics of hormonal secretion, which have to be evaluated. Objectives. To identify specific features of the endocrine system functioning related to reproduction in males living in the polar and sub - polar latitudes. Method. There were 149 men from two Northern regions were studied: 97 men in Arkhangelsk (sub-polar regions) and 52 men from Nesh (polar region), they were divided into three age groups: group 1 - 22-35 years (n=54 and 17, respectively), group 2 - 36-45 years (n=22 and 13, respectively), group 3 - 46-60 years (n=21 and 22 respectively). Results. It has been shown the absence of age-related dopamine dynamics with lowering the fluctuation limits at the age of 46-60 years in men from Arkhangelsk. Men aged 46-60 years from Nesh demonstrated increase in sex hormone binding -globulinand FSH levels and offset of dehydroepiandrosterone sulfate fluctuation limits to lower-normal range. There were positive correlation of the dopamine level with the levels of estradiol and sperm antibodies in men from Arkhangelsk (r=0.26; p=0.024; r=0.33; p=0.002 respectively) and the negative correlation of the dopamine level with the levels of free testosterone and sex hormone binding -globulin in men from Nesh (r=-0.34; p=0.047;r=-0.31; p=0.07 respectively). Conclusion. There were several specific endocrine features related to secretion/relationships of dopamine, estradiol, FSH, androgens, sex hormone binding -globulin identified in males living in the polar and sub-polar regions.