[Relationship of vitamin A and thyroid function in Arctic residents].

At the present time the prevalence of thyroid diseases keeps growing, so knowledge of the factors affecting thyroid activity is very important. Vitamin A (retinol) is a fat-soluble vitamin with a hormone-like effect that can influence both the expression of thyroidstimulating hormone in the pituitary gland and the synthesis of thyroid hormones. The aim of the research was to study vitamin A serum level and its relationship with the thyroid profile in residents of the Arctic zone of the Russian Federation, depending on gender. Material and methods. In the course of a single-center observational cross-sectional study, 304 apparently healthy residents of villages in the Arkhangelsk region (103 men and 201 women) were examined. The serum concentration of vitamin A was determined by the fluorometric method, and the content of thyroid parameters was determined by the enzyme immunoassay. The integral thyroid index (ITI) and the index of peripheral conversion of iodothyronines (IPC) were calculated. The subjects were divided into 4 groups depending on the quartile of vitamin A. The relative risk of developing subclinical hypothyroidism was calculated with a reduced concentration of vitamin A. Results. The content of vitamin A was 1.97 (1.18; 2.97) µmol/l. Retinol levels in the female population were significantly lower than in the male population (1.85 vs 2.27 µmol/l, p<0.0001). Women in group 1 compared with group 4 showed significantly higher levels of thyrotropin (2.33 vs 1.40 µIU/ml, p=0.0002) and thyroxin (109.8 vs 99.4 nmol/l, p=0.010), while the ITI values, on the contrary, were the lowest (8.12 and 13.85 c.u., p=0.0002). The relative risk calculation showed that vitamin A levels below 1.39 µmol/L increase the risk of subclinical hypothyroidism in women by 2.01 times [95% confidence interval 1.07-3.78]. Men in group 4 compared with group 1 showed a lower content of thyroxin (83.0 vs 109.2 nmol/l, p=0.009) against the background of higher IPC values (0.019 vs 0.016 c.u., p=0.046). Conclusion. In the inhabitants of the Arctic, the content of vitamin A is within the reference values, however, in 24.3% of men, its level is above the norm. In women, the concentration of retinol is significantly lower, and its level of less than 1.39 µmol/l increases the risk of developing subclinical hypothyroidism by 2.0 times. Increased values of vitamin A in the inhabitants of the North cause lower levels of thyroxine and an increase in the peripheral conversion of iodothyronines, which is more pronounced in men.

[Study of the photoperiodic dynamics of the peripheral dopamine content in comparison with the thyroid profile in various groups of men from the European North].

BACKGROUND: Knowledge of the physiological mechanisms of adaptation arising in response to changes in photoperiods is especially important for residents of the European North. In the literature, there is practically no information about photoperiodic dynamics of serum dopamine level, despite its significant role in the regulation of the body's activity. The mutual modulating effect of the dopaminergic and thyroid systems is known. AIM: To show the ratio of dopamine levels and the content of hormones, protines and autoantibodies of the thyroid system, taking into account photoperiod of the year, in practically healthy populations of the European North. MATERIALS AND METHODS: Healthy male population (20 men) of Arkhangelsk was examined in various photoperiods of the year (80 samples): an increase in the length of daylight hours (March), its maximum duration (June), a decrease (September), and a minimum duration (December). The inhabitants of the settlements and the nomadic aboriginal population (100 men) were examined during 2 photoperiods of the year - March and December. The serum levels of iodothyronines, TSH, TG, antibodies to TPO, antibodies to TG and plasma level of dopamine were determined using ELISA methods. RESULTS: Residents of Arkhangelsk in June compared to December have higher levels of dopamine (0.502 and 0.365 nmol/l, p=0.01), T3 (1.09 and 0.94 nmol/l, p=0.003), T4 (113.45 and 99.03 nmol/l, p=0.0002). In September, compared with June, a decrease in dopamine (0.235 nmol/l, p=0.0003), T3 (0.92 nmol/l, p=0.004) was recorded with an increase in T4/T3 ratio from 106.54 to 117.89 units (p=0.006). The nomadic aboriginal population in March compared with December showed a tendency to a higher content of dopamine (0.00 and 0.394 nmol/l, p=0.07) with the decrease in fT4 (15.20 and  13.90, p=0.015), fT4/fT3 ratio from 3.13 to 2.28 units (p=0.006). In December, 67% of nomadic population had undetectable dopamine values (0 nmol/l) and 22% - excess dopamine values, in March 27% - excess values. CONCLUSION: Unidirectional changes in dopamine and thyroid activity in men of the European North were shown with their decrease during periods of decrease and minimum daylight hours and an increase during periods of increase and maximum daylight hours.

Distinctive features of the hypothalamic-pituitary-gonadal axis and the level of dopamine in men of the European and Asian North.

In recent years, there has been a decrease in reproductive potential, especially among residents of the Arctic territories, having the greatest stress from various body systems, including the state of the hormonal regulation of the male reproductive system. The study of the dopamine levels and the content of sex hormones in the male population of various Arctic regions is relevant due to the increased stress on the part of the dopaminergic system and the hypothalamic-pituitary-gonadal axis in residents of the Northern regions, as well as the lack of information about their interaction among the apparently healthy population. The aim of the investigation is to study the possible effect of various plasma concentrations of the dopamine on the content of sex hormones and sex-steroid-binding ß-globulin (SHBG) in apparently healthy men in the Arctic zone of the Russian Federation, taking into account the territory of residence. There were examined 181 men aged 22-60 years, living in the territories of the European and Asian North. The levels of sex hormones, SHBG, and dopamine were determined by the enzyme-linked immunosorbent assay. The inhabitants of the Asian North in comparison with the men of the European North have higher levels of dopamine, luteinizing hormone, progesterone, prolactin, estradiol and SHBG with decreased serum levels of free fractions of testosterone. Reference levels of dopamine in men from the European North are combined with the stimulatory effect of dopamine on LH levels, which may indicate an increase steroidogenesis. The high levels of dopamine in men from the Asian North are combined with increased level of estradiol, which may be related to the effect of dopamine on testosterone aromatization. The separate region with its ecological differences is characterized by the presence of features of compensatory-adaptive reactions of an organism in male representatives on the part of the dopaminergic system and the hypothalamic-pituitary-gonadal axis. The identified features can help in carrying out preventive measures aimed at preserving the male reproductive potential of the inhabitants of the Arctic territories.

[Autoantibodies to thyroid antigens levels in the population of the Russian Arctic at different levels of blood dopamine.]

Neuroimmunoendocrine regulation of the thyroid gland involves the use of autoantibodies as regulatory molecules to stimulate or reduce the activity of the tissues of the organ itself. A huge number of regulatory signal molecules and factors, acting directly or indirectly, often plays a much more significant role, both in ensuring normal activity and in pathological processes. In this regard, it was interesting for us to determine the possible effect of dopamine at its various concentrations in the blood on the levels of thyroglobulin and antibodies to thyroid antigens. A survey of 110 men and 206 women aged 22 to 75 years who were born and lived in the Arctic zone of the Russian Federation and had no diseases of the endocrine and immune system was conducted. Dopamine concentrations were determined in blood plasma, thyroid stimulating hormone (TSH), thyroglobulin (TG), antibodies to thyroperoxidase (at-TPO) and thyroglobulin (at-TG) in serum. Higher concentrations of thyrotropin and thyroglobulin and lower concentrations of at-TG and at-TPO were shown with increasing dopamine levels from undetectable values to normative and excess levels. We explain this by the influence of dopamine on a-adrenoreceptors of antibody-producing cells and changes in the secretion of immunoglobulins class G, subclasses of which include at-TG and at-TPO. The appearance of different from zero values of autoantibodies concentrations in themselves, we associate with the negative impact of the conditions of the North and the prenosological state of the organism. Their higher values in women with low levels of dopamine can be explained by the lack of its immunomodulatory activity.

[Pituitary-gonadal and pituitary-thyroid axis hormone serum levels in postmenopausal women of the European North of the Russian Federation, depending on the age.]

Using the methods of radioimmunoassay and enzyme immunoassay there were studied the levels of hormones of the pituitary-thyroid and pituitary-gonadal systems in the postmenopausal women of the European North of the Russian Federation in the second period of mature age, elderly and senile ages. The lower concentrations of total and free fractions of triiodothyronine and total thyroxin, testosterone, dehydroepiandrosterone sulfate, and estradiol were noted in the blood of investigated women in the senile age. Excess levels of thyroid-stimulating hormone were shown in 12,1% of people in the II period of mature age and 17,4% of people in the elderly age. The examined women showed signs of androgenization, manifested by elevated values of luteinizing hormone, testosterone and dehydroepiandrosterone sulfate. The levels of luteinizing hormone exceed the norm in 50% of persons of the second period of mature age, 18,2% of the elderly and 26,1% of the persons of senile age. The concentrations of testosterone and dehydroepiandrosterone sulfate exceed the norms established for the postmenopausal period in 15,4 and 91,7% of persons in the second period of mature age and in 11,4 of 84,2% of the elderly age. The greatest number of correlation interrelations of the studied hormones levels was noted in senile age.

[Levels of sex hormones, sex hormone binding globulin, antisperm antibodies and dopamine in postmanopausal women of nomadic and settled aboriginal and local caucasoid populations of the arctic territories.]

Positive changes in the society led to an improvement in quality and lifetime; as a result the menopause in women lengthens much longer, in light of this the relevance of studying hormonal changes increases, especially among the representatives of different groups living in the Arctic territories. The study was carried out on 138 women who included nomadic and settled aboriginal and local Caucasoid postmenopausal populations, permanently residing in the Arctic territories of Russia. The greatest difference in the studied blood indicators was shown between the local Caucasoid and aboriginal population. A greater imbalance in the content of dopamine in Aborigines compared with the European population was combined with a higher levels of prolactin, sex hormone binding globulin, antisperm antibodies and with lower concentrations of lutropine, progesterone, total and free testosterone. In the settled aboriginal population compared with nomadic one there were shown the larger proportion of people with low levels of dopamine, lutropine, follitropin and high levels of prolactin, sex hormone binding globulin in the presence of increased number of feedbacks in the hypothalamic-pituitary-gonadal system, which suggested more pronounced reduction of its activity. The evident imbalance of the dopamine content in the aboriginal population was combined with the absence of connections between dopamine level and the parameters of the hypothalamic-pituitary-gonadal system. Positive correlation between the contents of dopamine and lutropin in the European population suggested the stimulating effect of dopamine on the hypothalamic-pituitary-gonadal system. Affected by imbalanced dopamine content the decreased activity of gonadotropic pituitary gland function as well as the peripheral part of the hypothalamic-pituitary-gonadal system was registered in the aboriginal Arctic population in comparison with the local European one, which was more pronounced in the settled aboriginals.

[The content of dopamine and hormones of system "hypophysis - thyroid" in blood of nomadic, settled and local population of the Arctic.]

The examination was applied to the groups of nomadic, settled aboriginal and local Caucasian population of the Arctic, permanently residing in the North. The study was carried out in the same period of the year - the period of increasing of duration of daylight hours. The study covered 253 individuals aged from 21 to 50 years. Despite differences in life-style of nomadic and settled aborigines, the similar signs were established consisting in the higher functional activity of hypophyseal section of the "hypophysis - thyroid" system against the background of lower content of auto-antibodies to thyroid peroxidase under increasing of the level of dopamine in blood as compared with local Caucasian population of the Arctic. The variation of analyzed parameters in aboriginal population depending on life-style also is demonstrated. So, nomadic aboriginal population is characterized by higher content in blood of global and free fractions of triiodothyronine, lower index of peripheral conversion of iodothyronines, increasing of level of dopamine and adenosine mono-phosphate. In case of settled aboriginal population increasing of content of global and free thyroxine is typical. In case of nomadic aborigines an expressed dissonance in content of iodothyronines is established: shifting of limits of variations of global and free triiodothyronine aside of higher bounds of standard at shifting of limits of variations of free fractions of thyroxine aside lower bounds of standard. The positive correlation relationships are registered between content of dopamine, thyroid hormones and adenosine mono-phosphate are registered. They are more expressed nomadic aboriginal population.

[The dynamics of hormonal indicators in women of Arkhangelsk under stimulation of corticotropine].

The test with pharmaceutical "Synachten Depot", a synthetic analogue of corticotropine was carried out. The sampling consisted of 30 clinically healthy women aged from 20 to 30 years and residents of Arkhangelsk. The scheme of blood sampling provided basal sample, 30 and 60 minutes, I and 4 days after administration of pharmaceutical. After 30 minutes of testing, increase of level of cortisol (F), progesterone (Δ4 = p), testosterone, triiodothyronine (T3) and decreasing of level of insulin and follitropin were established After 60 minutes of testing maximal level of cortisol, high concentration of progesterone and triiodothyronine, increasing of levels of testosterone, estradiol and insulin and decrease of concentration of thyrotropin and prolactin were observed. Up to the first day, the tests registered decrease of level of cortisol, progesterone, testosterone, thyrotropin, thyroxine and triiodothyronine under increasing of content of follitropin, estradiol and insulin in comparison with basal test. Up to the fourth day, tendency of increasing of the level of progesterone and estradiol and decreasing of lutropin and testosterone as compared with initial levels were observed.

[Changes in serum hormone levels in the middle and gerontic aged inhabitants of Arkhangelsk due to the gender identity].

The serum hormone levels were studied among middle and gerontic aged residents of Arkhangelsk by enzyme immunoassay and radioimmunoassay. The significant increase of follicle-stimulating and luteinizing hormones levels in gerontic aged men was recorded in the presence of higher concentrations of these hormones in women. There was a statistical tendency of decrease in the level of testosterone in gerontic aged women compared to middle aged. Regardless of gender the lowering of the dehydroepiandrosterone sulfate content was observed in gerontic aged residents compared to middle aged. The criteria of functional activity reduction of the thyroid gland were a decrease in serum free thyroxine fraction levels in gerontic aged women and low concentrations of common triiodothyronine in middle aged men living in Arkhangelsk. Serum cortisol, insulin, estradiol, growth hormone had no significant age and sex differences in the present groups. The number of correlations was greater among the gerontic aged people in comparison with the middle aged, especially among women.

[The ratio of hormones of system "hypophysis - thyroid" with level of dopamine and cyclic adenosine mono-phosphate of males in European north].

The study sampling consisted of 96 males from Arkhangelsk and 52 males from village of Nes. The examination was carried out to find out predominant regulative effect of dopamine on the system "hypophysis - thyroid" depending on territory of residence. In males of Zapolyarye, against the background of higher levels of T4, fT3 and TSH and cyclic adenosine mono-phosphate in blood occurs decreasing of levels of thyroglobulin and dopamine in comparison with males of circumpolar territories in case of registration of positive correlation between levels of dopamine and fT3. In males from circumpolar territories age-related decreasing of range of variations of level of dopamine and fT4 under increase of concentration of TSH was registered. At that, negative correlation between content of dopamine and T4 was registered. The age-related dynamics of alteration of level of cyclic adenosine monophosphate with tendency to increase in males of Zapolyarye at the age of 36-60 years in comparison with age group of 22-35 years.

Effects of overweight and obesity on the spermogram values and levels of reproductive hormones in the male population of the European north of Russia.

The effects of excessive body weight and obesity on the reproductive potential of the male population of the Russian European North (Arkhangelsk), characterized by a specific northern adaptive metabolic type were studied. Spermogram values and levels of reproductive hormones were compared in men with normal and excessive body weights and with obesity, using body weight index and waist circumference as indicators of abdominal visceral obesity. Irrespective of the indicator used, the total count of spermatozoa and their concentration in the ejaculate were significantly lower in men with obesity than in overweight men. Serum testosterone concentration was lower in obese men in comparison with men with normal body weights. Higher spermatogenesis, but not testosterone values, were observed in men with excessive body weight vs. men with normal body weights or obesity, which was presumably a characteristic feature of the northern metabolic type.

[The age-related aspects of changes in hormones' level in hypophysis-thyroid and hypophysis-gonads systems in residents of Arkhangelsk].

The male permanent residents of Arkhangelsk were examined during the period of daylight hours minimal duration for the purpose to determine the age-related changes in hormones' level. In the age group of 36-45 years the level recession of progesterone, cortisol and testosterone free fractions against the background of broadening towards higher standard limit of fluctuations of steroid-binding beta-globulin level was demonstrated. In the age group of 46-60 years the rise of cortisol level and tendency to level recession of free thyroxin under thyrotrophic hormone level increase was registered. The hypophysial regulation consisted in lutropin and prolactin level lowering at the age of 36-45 years and in rise of thyrotrophic hormone level at the age of 46-60 years.

[Hypophysis--thyroid gland--gonads in boys of the pubertate period in south areas of Archangelsk region].

The hormonal level dynamics of hypophysis, thyroid gland and sex steroids was analyzed in respect to the puberty. Concentrations of gonadotropins and sex streroids were increased whereas concentrations of thyroid hormones was decreased. The amplitude of hypophysis and thyroid hormones were narrowed whereas the range of sex steroids was extended during the puberty. In early stages of puberty, the interhormonal correlations existed on some levels (hypophysis or peripheral gland), but in late stage the intersystem and polyhormonal relations were formed. Thyroid hormones play a leading role in sexual maturity regulation. The sexual maturity is prolonged, the variance of sexual stages being quite wide. The range of gonadotropin shifted to the left side in comparison with children in moderate latitudes.

[Immunologic characteristics of individuals working on the archipelago Spitzbergen]. / Immunologicheskie osobennosti u rabotaiushchikh na apkhipelage Shpitsbergen.

A complex effect with photo-periodic components and depending on the duration of stay on Shpitzbergen Archipelago of people working there, was revealed in respect to the serum concentration of Ig A, G, M. The monocytes, autoantibodies, and circular immune complexes were increased, whereas lymphocytes, T-cells, and natural killers were decreased in winter time.