INVESTIGATION OF PHYSICAL LOADING AND STRESS INFLUENCE ON THE STATE OF THY-ROID GLAND AT HYPOTHYROIDISM

Relevance. The hormones of thyroid glands (TG) take part in regulation of practically all types of metabolic processes and activity of visceral systems of organism. The normal level of thyroid hormones is obligatory part of adaptive reactions. At scientific investigations of functional state of TG under action of stress opposite changes of level of thyroid hormones were determined. It can be explained by influence of different of character and duration stress factors. The acute stress causes mobilization of organism in result of increasing of level of thyroid hormones together with cateholamines and corticosteroids. The long-term stress leads to decreasing of secretory function of TG. Thus under conditions of stress there is progressive exhaustion of functional state of TG after activation at continued influence of stressful factors. Physical activity can be method of prevention of disease and increasing of functions of organism. The regular moderate physical loading leads to increasing of resistance of organism to influence of stressful factors. The changes of function of TG depend on duration and intensity of loading. The aim of investigation is the study of com-bined influence of chronic emotional painful stress (CS) and moderate physical loading (MPL) on changes of morphological and functional state of thyroid gland at hypothyroidism (H). Materials and methods. Experiments were per-formed on 48 white laboratory sex matured male rats. Animals were divided on four groups: the fist – intact animals; the second – animals with H; the third – animals in the conditions of influence of CS and MPL; the fourth – animals with H in the conditions of influence of CS and MPL. The H was modelled by everyday addition of mercazolilum (dose 10mg/kg of body weight of animal) to drinking water during 15 days. The CS was modelled by 1 hour per day during 30 days. The MPL was modelled by running (15 min per day) in tread ban every day with velocity of tape 20m/min during 30 days. The functional activity of TG was estimated by the concentration of thyroid stimulating hormone of adenohypophysis (TSH), free triiodothyronine (fT3), free thyroxin (fT4) in blood plasma and calculation of thyroid index (TI) according to formula: ТІ=(fТ3+fТ4)/TSH. The morphological state of TG was studied by light and electron microscopy. The statistical analysis of results was processed using Student's test with Bonferroni-Holm correction in program Statistica 6.0. The differences were statistical significant at р<0,05. Results and their discussion. The combined in-fluence of CS and MPL did not cause significant changes of contents of TSH and iodine-containing hormones of TG in blood plasma in comparison to results of intact animals. The data of microscopic investigation of TG of rats under specified conditions confirm biochemical changes and detect about absence of negative action of long-term stress on thyroid indexes at MPL. However, immune ferment analysis of blood plasma, light and electron microscopy of TG of animals with thyroid hormones deficiency under combined influence of CS and MPL caused to more substantial changes of indexes of pituitary-thyroid axis (significant increasing of level of TSH, decreasing of contents of fT3, fT4 and TI) in comparison to results of animals with H. Conclusions. The moderate dynamic physical loading causes positive influence on structural and func-tional states of TG under action of long-term emotional painful stress but this effect is absent in conditions of hypothyroid dysfunction.