Chromium increases pancreatic metallothionein in the rat

The ability of chromium (Cr) salts to increase metallothionein (MT) levels in rat liver, kidney and pancreas, and its relationship with the presence o f toxic effects are reported here. Rats were injected subcutaneously with 0 , 10, 20, 30, 40, or 50 mg K2Cr2O7/kg and sacrificed 24 h later. Total Cr a ccumulation followed a dose-dependent pattern, levels in kidney being highe r than those in liver or pancreas, suggesting different tissue bioavailabil ities and accumulation patterns. Cr(IV) administration resulted in a tissue -specific MT induction: pancreas and liver showed five- and 3.5-fold MT inc reases, respectively; no increase was observed in the kidney. A positive co rrelation was observed between zinc and MT concentrations in liver, and bet ween total Cr and MT concentrations in pancreas. Serum cl-amylase activity showed a dose-dependent increase starting from 20 mg/kg, whereas serum gluc ose levels increased at doses higher than 30 mg/kg. Serum aspartate aminotr ansferase and alanine aminotransferase activities were increased in a dose- dependent manner, from 20 and 30 mg/kg, respectively. Our results showed th at treatment with Cr(VI) can induce MT synthesis in pancreas and suggests a subsequent binding of Cr to MT. Also, pancreas is a target organ for Cr to xicity, and the usefulness of alpha-amylase activity as a sensitive biomark er of Cr toxicity in human exposed populations merits further study. (C) 20 00 Elsevier Science Ireland Ltd. All rights reserved.