DETERMINATION OF TOTAL AND HEXAVALENT CHROMIUM IN BILE AFTER INTRAVENOUS ADMINISTRATION OF POTASSIUM DICHROMATE IN RATS

Total and hexavalent Cr were measured in bile samples obtained from cannulated bile ducts of male rats i.v. administered with potassium dichromate at various doses corresponding to 0.1, 0.5 and 1 mg of Cr. The evaluation of the hexavalent form was performed by separation with a liquid anion exchanger and electrothermal atomization-atomic absorption spectrophotometric determination. Within 2 h 1.35-2.23% of the chromium injected was recovered in bile as total Cr, the hexavalent form accounting for < 1% of the total Cr collected, which seems almost entirely excreted as trivalent Cr. Since Cr(VI) administered i.v. was quickly reduced to Cr(III) in blood, the possibility exists for Cr in trivalent form to penetrate into the liver cells and to be excreted in the bile, possibly by binding to a carrier such as the low-MW substance described by Yamamoto et al.