[Daily changes in the activity of the hypothalamus-hypophysis-adrenal system in animals with varying individual radiosensitivity].

Circadian variations in the functional activity of the hypothalamic-pituitary-adrenal (HPA) system of Wistar rats with different individual radiosensitivity were studied. The latter was measured using an adrenaline test. The rats that differed in their radiosensitivity showed dissimilar circadian changes which included the amplitude, position of acrophases, pattern of periodic processes in the HPA system. Radioresistant rats exhibited a smaller amplitude of changes in the HPA system and a significantly larger amplitude of variations of the effectors.