Reactivity of Stress-Implementing System under Conditions of Light Regime Change in Experiment

Influence of light exposure duration (model 18 : 6) on hormonal indices of stress-implementing system in laboratory animals blood is studied. Activity of stress systems central link was evaluated based on data on concentration of adrenocorticotrophic hormone, melatonin and β-endorphin in blood serum, observed during enzyme immunoassay. Reaction of peripheric link of the stress-implementing system was evaluated in blood smears based on results of qualitative count of catecholamine granules in erythrocytes. It was established, that variations of hormonal indices of the stress systems for laboratory animals depend on trigger factor activity periods. With increase of the experiment duration to 21st days the most pronounced reduction of melatonin, β-endorphin and increase of adrenocorticotrophic hormone concentration, as well as sharp increase of catecholamines level are observed in the blood serum. These hormonal changes develop as a result of failure of compensation mechanisms of the stress-implementing systems in connection with melatonin rhythms disturbance, that indicates the gradual development of the general adaptation syndrome.