Americium-241 in the Blood: In Vivo and in Vitro Observations

BRUENGER, F. W., STEVENS, W., AND STOVER, BETSY J. Americium-241 in the Blood: In Vivo and in Vitro Observations. Radiation Res. 37,349-360 (1969). The concentration in canine blood of trivalent 241Am that had been injected intravenously decreased at a rate comparable with those of divalent alkaline earths. A small fraction of the 241Am was associated with blood cells, but the major part was in the serum. Complexes with serum proteins were demonstrated in sera obtained at 1 and 5 minutes after injection. Americium-241 complexes with both transferrin and albumin were identified and isolated in in vitro experiments with human sera. The AmIII complex with transferrin is less stable under physiological conditions than either the FeIII- or PuIV-transferrin complex. Evidence was obtained for a third AmIII-protein complex.