[Morphological study of the kidneys of rats flown aboard biosatellite "Cosmos-936"]

Kidneys of SPF Wistar rats flown for 18.5 days aboard the biosatellite Cosmos-936 and sacrificed 4.5-13 hours or 25 days postflight were taken under morphological study. An exposure of rats to artificial gravity inflight brought about a smaller increase in the kidney mass and a better readaptation of animals on return to 1 g. It is suggested that blood redistribution in the kidneys due to renal circulation shunting and, possibly, fluid transfer from the vascular bed to interstitial space are the factors causing an increase in kidney mass. No differences in the kidneys of weightless and centrifuged rats were found.