[Experiments on rats exposed in the Cosmos 1667 biosatellite (goals, protocols, results)].

Morphobiochemical investigations of the rats flown on the biosatellite Cosmos-1667 have shown that the 7-day space flight produces shifts in different systems, organs and tissues which reflect adaptive processes to microgravity. Early signs of structural, functional and metabolic rearrangement can be detected in the musculoskeletal apparatus, hemopoietic system, lymphoid organs, neurohormonal systems, i.e., in the systems and organs that develop changes during long-term flights. The rates of adaptation to microgravity are different not only in various systems and organs but also within the same tissues. Most shifts that emerge at an early stage of adaptation to microgravity progress with flight time but some of them develop to a full extent after the 7-day flight. The specific feature of the early stage of adaptation to microgravity is the lack of significant changes in blood biochemistry in the presence of structural and metabolic changes in tissues. This fact gives evidence that the mechanisms maintaining homeostasis at the organism level are not as yet disrupted during 7 days of flight.