The effect of dehydration on erythroid progenitor cells in mice

Mice deprived of water for three days showed hemoconcentration due to a reduced plasma volume, suppressed erythropoiesis and reduced food intake. All three classes of erythroid progenitor cells in both the bone marrow and spleen of dehydrated mice were markedly suppressed but recovered rapidly upon rehydration. In addition, during dehydration the spleen cellularity was significantly decreased and was associated with an increase in the percentage of adherent cells. The changes in erythroid progenitor cells during dehydration are compared to previously published data on changes in these cell populations in erythrocytotic mice with similar hematocrits. This comparison indicates that, as we have suggested earlier, the major component producing the erythroid suppression in dehydrated mice is the reduced food intake. Hemoconcentration plays a minor role. The relevance of these changes to the "anemia of spaceflight" is discussed.