UDC

612.433/434’175.3(470.11)

Authors

Irina N. Gorenko*
*Federal Center for Integrated Arctic Research, Russian Academy of Sciences (Arkhangelsk, Russian Federation)
Corresponding author: Irina Gorenko, address: prosp. Lomonosova 249, Arkhangelsk, 163000, Russian Federation; e-mail: pushistiy-86@mail.ru

Abstract

It is well-known that the population of the European North of Russia is heterogeneous in social and demographic terms and varies in the degree of adaptation to negative climatic and environmental factors; an essential role in this process is played by the thyroid gland. We analysed the functional state of the pituitary-thyroid system in healthy men permanently residing in Arkhangelsk and Nes village (Nenets Autonomous Area, 66°39’N). The concentration of hormones of the pituitary-thyroid system (total and free thyroxine, total and free triiodothyronine, and thyroid-stimulating hormone) was determined by enzyme-linked immunosorbent assay. Universal thyroid indices were calculated: index of peripheral conversion (FT₃/FT₄) and integral thyroid index ((FT₃+FT₄)/TSH). The results revealed no age-related dynamics in the index of peripheral conversion in healthy men of Arkhangelsk and Nes village. However, this index was lower in men living in Arkhangelsk compared to those living in Nes village. The integral thyroid index in men of Arkhangelsk was significantly lower in the group aged 46–60 years compared to the groups aged 22–35 and 36–45 years; at the same time, this parameter did not vary between the age groups of men from Nes village. The analysis of the data showed that conversion of peripheral hormones in men from Nes village shifted towards the formation of the most active metabolite: free triiodothyronine. In addition, we found that the integral thyroid index was higher in men from Arkhangelsk aged between 22 and 45 years compared to their peers in Nes village, with 17 % of the subjects exceeding the upper limit of normal.

Keywords

FT3/FT4 ratio, (FT3+FT4)/TSH ratio, pituitary-thyroid system, men of the European North of Russia

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