[Morphologic study of rat adrenals following flight aboard biosatellites "Cosmos-605" and "Cosmos-782"]

Dynamics of morphological changes of the rat adrenals was investigated on the first day and 25--27 days after a prolonged exposure to weightlessness. Analysing the general histological picture of the adrenal cortex during the first hours of the flight (presence of a subglomerular sudanophilic layer and distinct zones in other cortical parts), it is possible to conclude that by the completion of the flight the cortical substance has reached a definite degree of normalization, hence the animals have adopted to the flight conditions. Morphological signs of elevated functional cortical activity 9--11 h after the flight, such as enlarged nuclear volume of the fascicular zone cells and delipoidization of the internal parts of the cortex could be treated as manifestation of an acute stress-reaction developing in the animals after landing. Evaluating morphological manifestation of the acute stress-reaction observed in animals at transition from weightlessness to the earth level of gravitation, it is possible to conclude that there are no signs of depletion in the adrenal cortical function and hence, adaptive possibilities in the organism are preserved after a prolonged exposure to weightlessness.