Biliary Excretion of Chromium in the Rat: A Role of Glutathione

The relative amount of chromium excreted in rat bile after injection of Cr-III is much less than after injection of Cr-VI, about 0.1% and from 6-8% during 5 hours respectively, for corresponding dose levels. The liver to bile ratio was 50-100 for Cr-III injection, for Cr-VI the ratio was 2-3. With doses up to 18 mumol Cr/kg, only Cr-III was found in bile even after injection of Cr-VI. Glutathione depletion of the liver with cyclohexene oxide decreased chromium excretion in bile. Such treatment also decreased the reduction of Cr-VI to Cr-III in the liver cell as only Cr-VI was found in bile. A different distribution of Cr-III in the liver dependent on whether derived from Cr-VI or taken up by the liver as such must be assumed. Taking into account the usual low penetration of biological membranes by Cr-III, a possible active transport mechanism or a specific diffusable Cr-III compound must be postulated.