EFFECT OF CHELATION ON THE ABSORPTION OF CADMIUM FROM RAT INTESTINE INVIVO

The intestinal absorption of 109CdCl2 (500 nmol) and some cadmium complexes (500 nmol) was investigated in rats. CdCl2, or Cd complexed with cysteine or glutathione showed very similar absorption patterns, since 109Cd uptake by the intestinal epithelium was high (approximately 350 to 400 nmol after 120 min) but the amount transferred (i.e. absorbed) was relatively low (approximately 7 to 8 nmol after 120 min). Most of the transferred 109Cd was rapidly taken up by the liver; renal 109Cd uptake was low. Chelation with EDTA or BAL decreased both intestinal uptake and transfer relative to CdCl2. CdBAL and CdEDTA also altered the subsequent distribution pattern. CdEDTA resulted in high renal 109Cd concentrations and lowered hepatic 109Cd concentrations. CdBAL resulted in increased hepatic 109Cd concentrations but very low renal 109Cd concentrations. Cdcys and CdGSH may dissociate in vivo to release the free cation. By contrast CdEDTA and CdBAL appear to be stable and remain undissociated. The chelation of Cd can thus alter its absorption and distribution pattern. © 1979.