BACKGRAUND
The problem of studying the regulatory effect of peripheral dopamine levels on the functional activity of the hypothalamic-pituitary-gonadal axis, especially in apparently healthy residents of the northern territories, remains not fully understood.
AIM
To study the content of sex hormones in men with different natural levels of dopamine in the blood, given the nature of the lifestyle in the permanent residents of the Russian Arctic zone.
MATERIALS AND METHODS
The analytical study in the period of increasing daylight hours (March) included 103 apparently healthy men aged 22—60 years. According with the way of life, the subjects were divided into the indigenous and settlement population (sedentary aborigines and the local Caucasian population that had been living in the North for at least 3 generations). These groups were considered taking into account the plasma levels of dopamine: undetectable values (I), reference values (II), increased values (III). The levels of sex hormones and dopamine were determined by enzyme immunoassay.
RESULTS
Among the indigenous and settlement population, the percentage of persons with undetectable levels of dopamine in the blood was 11.9 and 8.2%, with the reference level — 59.5 and 65.6%, with increased — 28.6 and 26.2%, respectively. In indigenous population (reindeer herders) of Group II, we found an increase in the concentration of lutropin (p=0.001) and estradiol (p=0.009), a decrease in testosterone level (p=0.005) relative to Group I. In Group III, the content of prolactin was decreased (p=0.024) and the level of estrone was increased (p=0.04) relative to Group II; as well as the levels of testosterone (p=0.04) and testosterone/estradiol ratio (p=0.009) were decreased and the level of estradiol were increased (p=0.007) relative to Group I. In the settlement population in Group II and in Group III we found an increased lutropin level (p=0.04; 0.018) relative to Group I; and increased estrone level (p=0.003) in Group III relative to Group II. A specific feature of the indigenous population relative to the settlement population was a higher testosterone/estradiol ratio (p=0.012) in Group I, a higher frequency of detecting increased prolactin values (32% of individuals relative to 15% in settlement population, p=0.05) and a lower progesterone (p=0.001) in Group II.
CONCLUSIONS
More pronounced changes in the reproductive hormones associated with the level of dopamine in the blood were shown among the indigenous population compared with the settlement population, which can serve as both an adaptation factor and a prognostic marker of a decrease in the functional activity of the hypothalamic-pituitary-gonadal axis.
