Space flight effects on the hemopoietic function of bone marrow of the rat.

The 22-d orbital flight of rats onboard the Cosmos-605 biosatellite was followed by inhibition of erythroblastosis, alteration in the morphology of megakaryocytes, and stimulation of myelopoiesis. These changes returned to normal 27 d postflight. The colony-forming capacity and pattern of differentiation of hemopoietic stem cells of bone marrow of flight rats remained undisturbed.