CADMIUM INHIBITION OF VITAMIN-D-MEDIATED RESPONSES IN ORGAN-CULTURED EMBRYONIC CHICK DUODENUM

When added to the medium, cadmium (4 × 10-5 m) inhibits 1α,25-dihydroxycholecalciferol (1α,25-(OH)2D3)-mediated responses in the organ-cultured embryonic chick duodenum: decreases induction of a specific calcium-binding protein (CaBP), prevents the elevation of alkaline phosphatase activity, and reduces the ability of the tissue to absorb radiocalcium at the mucosal surface. The cadmium effect is clearly not generalized cytotoxicity: total protein concentration actually increased after cadmium treatment, and the effect of a 24-hr culture in the presence of cadmium is largely reversed during a subsequent 24-hr period. These results may be taken as evidence that cadmium can interfere with vitamin D action at the level of the target organ itself and is not necessarily secondary to alteration in vitamin D metabolism. © 1979.