Identification of transferrin as the principal plutonium-binding protein in the blood serum and liver cytosol of rats: immunological and chromatographic studies.

An analysis of 239Pu-labelled protein complexes in serum and liver cytosol fractions prepared from rats injected intravenously with 239Pu-citrate indicated that among the possible metal-binding proteins, ferritin, transferrin and metallothionein, 239Pu was bound almost exclusively to transferrin. The method employed for the quantitative determination of 239Pu-transferrin was chromatography on immobilized rabbit anti-rat apo-transferrin. There was no evidence that transferrins from serum and liver cytosol are serologically different. The residual blood content of perfused and non-perfused liver was measured using 51Cr-labelled red blood cells and the amounts of blood-derived 239Pu and 239Pu-transferrin in the liver cytosol were calculated. The results are discussed with respect to the possible role of transferrin in the uptake of Pu into cells.