[Functional state of the posterior lobe of the neurohypophysis of rats exposed aboard the biosatellite "Cosmos-936" (according to the results of morphologic studies)].

A comparative evaluation on some morphological indices of functional state of the posterior neurohypophysis was performed in rats subjected to weightlessness and artificial gravitation for 18.5 days on board the biosatellite "Cosmos-936". The data of the investigation were compared to those obtained on the test animals used for terrestial series of the experiment where all the factors of space flight, except weightlessness were imitated. As the analysis of morphological data demonstrated, a prolonged effect of weightlessness results in a considerable decrease in the number of the neurosecretory cumulative corpuscles (Herring's bodies), in decreasing volume of nuclei and size of pituicytes. A suggestion is made on decreasing basal level of functional activity of the hypothalamo-hypophyseal neurosecretory system under the conditions of weightlessness. Administration of artificial gravitation (lg) levels partly the changes produced by weightlessness and ensure a higher level of functioning in the neurosecretory system.