Biliary and gastrointestinal excretion of chromium after administration of Cr-III and Cr-VI in rats.
Rats treated intravenously with 51Cr-labelled sodium chromate, 0.1 or 100 microgram Cr/rat, excreted more 51Cr into bile in a 2-hr period than did the animals given equal amounts of chromium in the trivalent state. Distinct patterns of hepatic intracellular distribution of the radiotracer were also observed. In the Cr-VI rats over 50% of the liver chromium was present in the supernatant fraction whereas in the Cr-III rats almost all the liver radioactivity was localized in the cell organelles. Fractionation of bile on Sephadex G-75 demonstrated binding of chromium to low-molecular weight substances. It is suggested that complexes of chromium with low-molecular weight components of liver cytosol are involved in the passage of this element from the liver to bile. A low cytosolic content of diffusable Cr-complexes associated with the incorporation of a large fraction of liver chromium in cell organelles may be a factor contributing to the low rates of 51Cr biliary excretion in the animals given Cr-III. 24 hr after the injection of 51Cr to bile duct-ligated rats appreciable levels of radiotracer were found in the gastrointestinal tract. The animals given Cr-VI exhibited significantly higher values of chromium content in the gut than those treated with Cr-III.
D000818:Animals; D001646:Bile / Q000032:analysis*; D001652:Bile Ducts / Q000378:metabolism*; D002857:Chromium / Q000378:metabolism*; D004064:Digestive System / Q000378:metabolism*; D005243:Feces / Q000032:analysis; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats
D002857:Chromium