[The population variability of cortisol and thyroid hormone levels in northern Khanty]

The cortisol, thyroid-stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3) levels were studied in the north Khanty population. 718 individuals of both sexes aged over 10 years were examined in August, November and December. The cortisol and TSH levels were characterized by nonlinear age dependence. Negative linear correlations between age and hormone levels were more obvious for T3 and T4 and higher in males. The mean plasma cortisol and T3 levels were significantly higher in males. Significant seasonal differences in T4 levels were observed, the minimal mean values having been found in August.