Comparative toxicity of trivalent and hexavalent chromium V: Enzymatic alterations in rat liver and kidneys.

The effect of trivalent and hexavalent chromium compounds on the activities of selective hepatic drug metabolising enzymes and renal enzymes, in relation to the duration of exposure and tissue concentration of the metal in rats, was investigated to evaluate their potential toxicity. The activity of hepatic aniline hydroxylase decreased more markedly than that of amino N-demethylase on treatment with Cr irrespective of valence state. The activity of hepatic glutathione S-transferase decreased with duration of treatment with Cr+6, more significantly than with Cr+3. On the other hand, the levels of renal glutamic oxalacetic transaminase, acid phosphatase and lactic dehydrogenase were lowered significantly on treatment with Cr" only. The liver and blood concentrations of Cr increased with duration of exposure, more markedly in animals exposed to Cr+6. The uptake of renal Cr was however very slow and was independant of valence state of the metal.