Indicators of the pituitary-gonadal axis and cortisol level, depending on the individual-typological reaction of the dopaminergic system, to changes in the photoperiod of the year in males living in the European North

Abstract

The aim of the work is to compare the reaction of the pituitary-gonadal system and the cortisol content in two types of dopaminergic system reactions in male residents of Arkhangelsk at the change of the photoperiod during the year. Material and methods. During one year, a four-time examination was conducted (in March, June, September, December) of 20 practically healthy males in Arkhangelsk (average age 33.3 ± 5.3 years). The concentration of dopamine was determined in blood plasma, the components of the pituitary-gonadal system and cortisol level were studied in serum. Based on the analysis of individual reactions, the sample was divided into two groups: 1 – the concentration of dopamine in the subjects increases in December compared with September (n = 10); 2 – the concentration of dopamine decreases or does not change in December compared with September (n = 10). Results. In group 1, a decrease in testosterone levels was revealed: both total (18.16 nmol/l in December and 25.20 nmol/l in September) and free (3.77 and 4.29 pg/ml, respectively) fractions. At the same time, a higher cortisol content was noted in December in the first group compared with the second (574.22 and 502.69 nmol/l, respectively). In group 2, there was a significant decrease in estradiol levels (0.13 nmol/L in December versus 0.31 nmol/L in September) with an increase in the testosterone/estradiol index (173.82 and 54.01 units, respectively). Conclusions. The individual-typological variability of the dopaminergic system in the replacement of photoperiods in males living in the European North may have an indirect effect on the pituitary-gonadal axis through parallel activation of the adrenal cortex and increased aromatase activity. We assume that an increase in dopamine content during the period of minimum daylight hours plays a significant role in the compensatory adaptive increase in estradiol levels in the male population of the North.

Keywords

• dopamine
• cortisol
• sex hormones
• aromatase
• photoperiod
• daylight duration
• european north
• males
• individual reactions