Release of Cr(III) from Cr(III) picolinate upon metabolic activation

Hexavalent and trivalent chromium are released into the environment from a number of different industrial activities. It is known that Cr(VI) can be r educed and subsequently complexed by humic acids to produce Cr(III) humic a cid complexes in the soil and aquatic environments. The metabolic fate of C r(III) humic acid complexes and other Cr(III) organic complexes in mammalia n systems is unknown. Therefore, Cr(III) picolinate was chosen as a model c omplex for Cr(III) humic acid complexes and other environmentally relevant Cr(III) complexes. Both human hepatocyte microsomes and primary cultures of chick hepatocytes were used to generate metabolites of Cr(III) picolinate. The results from both of these treatments show that a significant amount o f Cr(III) is released (66 and 100%, respectively) and that N-1-methylpicoti namide is the primary organic metabolite from this compound. These data suggest that the populations of humans who are exposed Cr(III) p icolinate or other environmentally relevant organic Cr(III) complexes, such as Cr(III) humic acid complexes, are potentially accumulating high levels of Cr(III) intracellularly. This intracellular accumulation of Cr(III) can result in the formation of covalent bonds between Cr(III) and DNA and/or ot her macromolecules, causing genotoxic effects. These data should be conside red when assessing the risk of an area contaminated with chromium. (C) 2001 Elsevier Science B,V, All rights reserved.