Department for Experimental Physiology and Pharmacology, Almazov National Medical Research Centre, St. Petersburg, Russia.
Laboratory of Byophysics of Blood Circulation, First Pavlov State Medical University of St. Petersburg, St. Petersburg, Russia.
Chronobiol Int. 2021 Mar;38(3):301-317. doi: 10.1080/07420528.2020.1865394. Epub 2021 Feb 3.
Seasonal dynamics in biological functions of mammals is regulated by melatonin-mediated circannual fluctuations in the secretion of thyroid-stimulating hormone (TSH) and thyroid hormones. Most anatomical and molecular structures responsive to photoperiod and melatonin secretion changes and the associated receptors are preserved in modern humans. This work aimed to determine the seasonal dynamics of TSH and thyroid hormone levels (total triiodothyronine (T3), free triiodothyronine (FT3), thyroxine (T4), free thyroxine (FT4) and to investigate the dependence of these variations on gender, age and amplitude of meteorological fluctuations. A meta-analysis of 13 panel and 7 cross-sectional studies was performed using Review Manager 5.3 (Cochrane Library). We found that circulating TSH levels were higher in winter than in other seasons, and FT4 levels were higher in autumn than in winter. T4 level had no pronounced seasonal dynamics. The level of circulating T3 was significantly higher in winter than in summer and FT3 levels were lower in summer than in autumn and spring. In addition, analysis of TSH seasonal dynamics (winter vs summer) accounting for gender differences showed pronounced increases in TSH levels during winter in women, but not in men; and also significant increases in FT4 levels during summer in men, but not in women. Seasonal dynamics of FT3 and T4 did not depend on gender. Seasonal dynamics of TSH did not change with respect to age. We also found that the extent of the seasonal dynamics of TSH is influenced by the extent of the annual dynamics of the partial density of oxygen in the air, as well as the magnitude of the annual dynamic of meteorological factors that determine it (atmospheric pressure and relative humidity).
哺乳动物的生物功能季节性动态受褪黑素介导的促甲状腺激素 (TSH) 和甲状腺激素的年周期波动调节。大多数对光周期和褪黑素分泌变化以及相关受体有反应的解剖学和分子结构在现代人类中得以保留。本研究旨在确定 TSH 和甲状腺激素水平（总三碘甲状腺原氨酸 (T3)、游离三碘甲状腺原氨酸 (FT3)、甲状腺素 (T4)、游离甲状腺素 (FT4)）的季节性动态，并研究这些变化对性别、年龄和气象波动幅度的依赖性。使用 Review Manager 5.3（Cochrane 图书馆）对 13 项面板研究和 7 项横断面研究进行了荟萃分析。我们发现，循环 TSH 水平在冬季高于其他季节，FT4 水平在秋季高于冬季。T4 水平没有明显的季节性动态。循环 T3 水平在冬季显著高于夏季，FT3 水平在夏季低于秋季和春季。此外，对 TSH 季节性动态（冬季与夏季）进行性别差异分析显示，女性冬季 TSH 水平明显升高，但男性没有；男性夏季 FT4 水平也显著升高，但女性没有。FT3 和 T4 的季节性动态不受性别影响。TSH 的季节性动态与年龄无关。我们还发现，TSH 季节性动态的程度受空气中部分氧气密度的年动态以及决定其的气象因素的年动态幅度的影响（大气压和相对湿度）。
