SUMMARY Objective: To study the uptake of lanthanides by human erythrocytes (HRC) and rabbit intestinal brush border membrane
vesicles (BBMV) and the influence of bovine serum albumin (BSA), citric group (Cit 3- ) and divalent metal
ions M 2+ (Cu 2+ ,Co 2+ ,Zn 2+ ,Cd 2+ , Pb 2+ ).Methods: After incubation of HRC or BBMV with Ln 3+ in the presence or absence of BSA (or Cit 3- , M 2+ ) in solution, the contents of Ln and M in cytoplasm, membranes and BBMV were determined by ICP or ICP MS. Results: These Ce 3+ ,Gd 3+ ,Yb 3+ ions studied could pass through cellular membrane into HRC, BSA promoted the transmembrane transport for Ce 3+ and Yb 3+ , but the effect was not observable for Gd 3+ . After incubation of Ce 3+ and Pb 2+ , Cu 2+ , Co 2+ , Zn 2+ respectively with HRC, the
binding amounts of Ce 3+ to cellular membranes were not changed significantly compared with the incubation of HRC and Ce 3+ , but Cu 2+ elevated obviously the content of Ce in cytoplasm. Ce 3+ ions promoted Co 2+ ions to enter HRC. However, Co 2+ and Zn 2+ almost completely inhibited the transmembrane transport of Ce 3+ ions. BBMV could bind to Ce 3+ , Gd 3+ , Lu 3+ and Cu 2+ , Pb 2+ , Cd 2+ ions, Cit 3- inhibited the binding of Ln 3+ to BBMV and the inhibition rates increased with stability of complexes
3- . Ce 2+ and Pb 2+ or Cd 2+ ions inhibited each others binding to BBMV, butCu 2+ displayed promotion for binding of Gd 3+ to BBMV. Conclusion: In vitro experimental results indicated that there was antagonism or cooperative interaction between Ln 3+ and M 2+ in the uptake of human erythrocytes and BBMV for Ln 3+ and M 2+ ,and the interactions depended on the natures of Ln 3+ and M 2+ .