RBC-51Cr half-life and albumin turnover in growing beagle dogs during chronic radial acceleration.

The effects of chronic centrifugation on growing Beagle dogs exposed to -2 or -2.6 Gx on albumin and RBC turnover rates, albumin concentration and space, and total blood volume were determined and compared with caged and run control animals. Albumin-125I and autologous RBC-51Cr preparations were injected into all dogs at day 82 of the centrifugation period and the disappearance curves were determined by successive bleedings of the animals over the next 35 d, during which the centrifugation was continued. There were no differences in albumin turnover rates or space. Two populations of RBCs were found in both centrifuged groups, one with a normal half-life of 27 +/- 1 S.E.M. d, and one with a significantly ( less than 0.01) shorter half-life of 15 +/- 2 S.E.M. d. An absolute polycythemia was also observed in both centrifuged groups. The results suggest that chronic centrifugation acts through some as yet unknown mechanism to affect RBC population kinetics.