COMPARATIVE GENDER ANALYSIS OF PHOTOPERIODIC DYNAMICS OF THE THYROID PROFILE, THYROID ANTIBODIES AND DOPAMINE IN BLOOD OF PEOPLE LIVING IN ARKHANGELSK

Investigation of the thyroid and dopamine-ergic system functioning in female population is of particular interest in context of the physiological relation between the thyroid gland and reproductive status, dopamine-ergic (DES) and hypothalamo-hypophyseal-thyroid (HHTS) systems, and their dependence on photoperiod. Our purpose is to determine gender-related specifics of the HHTS and DES activities in essentially healthy people in the European North with consideration of the contrast photoperiod. Participants were 40 people (20 men and 20 women at the age of 22 to 44 years) examined in four seasonal photoperiods (March, June, September, December). EIA was used to investigate serum levels of thyroid hormones, thyroglobulin (TG) and thyroid autoantibodies (anti-TG, anti-TPO), and plasma dopamine; indices of iodothyronins peripheral conversion (PCI and PPCI) were calculated. Averaged through the year values showed that levels of Т3, Т4, fТ3, ТH, antiTH, antiTPO, dopamine were higher and TTH, fТ4, PCI (Т4/Т3), PPCI (fТ4/fТ3) lower in women in comparison with men. In contrast to men, women were more sensitive to photoperiodic dynamics. Thus, free iodothyronine fractions decreased in September and December, and PPCI in December. T3 made an increase by December, while Т4 and antiTPO grew in September. High dopamine levels were more frequent in women than in men, in June in particular (35 % and 20 %, respectively). Increases of dopamine in the period of maximal daytime were simultaneous with growth of the HHT activity. As daytime diminished, activities of these systems also decreased pointing to the common response to the seasonal photoperiodic dynamics. Sensitivity of the female HHT and DA systems to the daytime changes is likely related to the sex hormone production.