[The hematological status of rats born and raised under increased gravitational force]

Blood and bone marrow morphology of the rats the pre- and postnatal development of which up to the ages of 60 and 75 days took place under 2g environments induced by a continuous centrifuge rotation. The response to a reduced gravity was studied in 60-day-old rats on post-rotation days 2 and 15. Immediately post-rotation, these animals exhibited: an intensified erythropoiesis resulting in an elevated erythroid cell counts, an activated eosinophilopoiesis and decreased level of neutrophilopoiesis. Return of the animals to a terrestrial environment during a 2-week period has caused a greater increase of erythroid production and the tendency toward normalizing granulocytopoiesis. In the 75-day-old rats developed under 2g, erythro- and granulocytopoiesis have tended to be recovered and bone marrow population of lymphoid and plasma cells was significantly decreased. The results point to the fact that hemopoiesis adaptation to an increased gravity during the studied period of time is not accomplished and this hematologic status depends on a changed status, of the controlling systems.