Blood levels of hexavalent chromium in rats. "In vitro" and "in vivo" experiments.

For the Cr(VI) selective separation from biological materials we have developed a highly rapid extraction-separation method with liquid anion exchanger as Amberlite LA-1 or LA-2. The analytical determination of Cr(VI) in organic phase was carried out using electrothermal atomic absorption spectroscopy (ETA-AAS). After i.v. administration of 0.5 and 2.5 mg/kg b.w. of K2Cr2O7 in male Wistar rats the biological samples, collected at different times, were immediately analyzed. Cr(VI) was not detected in whole blood one minute after administration of the lower dose. In blood of rats receiving higher dose an incomplete reduction of Cr(VI) was observed. Such data demonstrate a highly rapid but limited metabolic capacity of hematic compartment to reduce Cr(VI) to trivalent status. "In vitro" incubation of K2Cr2O7 (4 microM) with rat erythrocytes or plasma at 37 degrees C showed a rapid reduction of Cr(VI) in red cells while plasma samples demonstrated a limited reductive power. These results obtained with a new and specific analytical method, confirmed a trigger role of red cells in Cr(VI) metabolism.