Dynamics of hormone and metabolic state in polar inhabitants depend on daylight duration.
Fluctuations in the level of TSH, T3, T4 and total cholesterol were determined in male aborigines and native polar inhabitants in different photoperiods of the year. It was found that a rise of serum TSH and T3 and a reduction of the thyroxine level and total cholesterol occurred in both population groups with the lengthening of daylight duration. However, the amplitude of annual fluctuations in the studied variables was different. There was a significant correlation between TSH, T4 and T3 levels and daylight duration. The photoperiodical contrasts of the polar regions are probably important in the formation of the annual fluctuations of hormone levels of the hypophysis-thyroid gland system and total cholesterol.
Tkachev
A V
AV
Institute of Physiology, USSR Academy of Sciences, Archangelsk.
Ramenskaya
E B
EB
Bojko
J R
JR
D000328:Adult; D001110:Arctic Regions; D002784:Cholesterol / Q000097:blood*; D003081:Cold Climate; D006728:Hormones / Q000097:blood*; D006801:Humans; D008027:Light; D008297:Male
D006728:Hormones; D002784:Cholesterol