Metabolic fate of chromium compounds. I. Comparative behavior of chromium in rat administered with Na251CrO4 and 51CrCl3.

Abstract

Comparative metabolic fate of labeled CrCl3 and NaCrO4 and interaction of these compounds in the rat liver and blood were investigated after their oral and i.v. administration. Gastrointestinal absorption of both compounds was below 1% of the oral dose, but trivalent Cr showed higher radioactivity than the hexavalent form in rats (biological half-life: CrCl3 91.79 days, Na2CrO4 22.24 days). The higher residual activity of the trivalent Cr was observed after i.v. administration. Both forms of Cr were excreted more in the urine via the kidney than in the intestinal tract after i.v. administration. When 51CrCl3 and Na2 51CrO4 were injected into rats, in the time distribution patterns of 51Cr in the organs, a significant difference was shown between oxidation states of the 2 compounds, especially in subcellular fractions of the liver and blood constituents. This significant difference mainly observed in the rat blood came from the fact that trivalent Cr possessed a high binding activity for transferrin in plasma, while hexavalent Cr was permeable into red cells and bound with Hb. CrCl3 is less toxic than NaCrO4 in animals.