Effect of phloridzin and ouabain on cadmium and zinc absorption using an isolated perfused rat intestinal preparation

The action of phloridzin and ouabain on Zn and Cd (as well as glucose) absorption was studied using an isolated vascularly and luminally perfused rat preparation. Phloridzin and ouabain (both at concentrations of 1 x 10(-4) M) significantly decreased glucose uptake. The addition of phloridzin (1 x 10(-4) M) to the luminal medium (LM) which contained either Cd (0.1 mg/L, 0.89 mumol/L) or Zn (5 mg/L, 76.45 mumol/L) led to a significant decrease in the appearance of Zn and Cd in the vascular effluent (VE). Phloridzin also significantly increased the perfused tissue content (ie, jejunum and ileum) of Cd and Zn. The addition of ouabain (1 x 10(-4)) to the vascular medium resulted in similar effects: a decrease in Cd and Zn appearance in the VE and an increase in Cd and Zn tissue content post perfusion. When both metals were present in the LM, Cd significantly decreased Zn VE appearance and increased Zn tissue content, while Zn significantly increased Cd VE appearance and decreased Cd tissue content. The further addition of either phloridzin to the LM or ouabain to the VM led to no further changes. The results of this study demonstrate that it is likely that Zn and Cd absorption are related to glucose absorption and sodium ion fluxes, with the predominant effect perhaps being at the basolateral membrane.