Effects of Zinc and Copper on Uptake of Cadmium by LLC-PK₁ Cells

抄録

Effects on zinc (Zn) and copper (Cu) on cadmium (Cd) accumulation were investigated in LLC-PK₁ cells. Coincubation with Zn or Cu decreased Cd uptake by the cells in a concentration-dependent manner. Cd accumulation data suggested that Cd is taken up by the cells via simple diffusion and carrier-mediated transport. Zn and Cu significantly increased the K_m of Cd uptake with no or little effect on the V_max. Pretreatment of the cells with ouabain and a metabolic inhibitor (FCCP) significantly decreased Cd accumulation, and coincubation with Zn or Cu led to an additional decrease in Cd accumulation by these cells. Overall, it seems that, in addition to simple diffusion, Cd is also taken up by LLC-PK₁ cells via carrier-mediated mechanisms that are competitively inhibited by Zn and Cu.