Uptake and subcellular cleavage of organomercury compounds by rat liver and kidney

Abstract

The uptake and transformation of phenylmercuric acetate (PMA), ethylmercury chloride (EMC), and methylmercury chloride (MMC) by rat liver, kidney, and brain slices were investigated. A slightly greater enzymatic activity for the cleavage of PMA and EMC was observed in the kidney than in the liver; brain tissue had the least activity. The average rates of C-Hg cleavage were 2.4 to 3.0 nmole g −1 h −1 for PMA and 0.9 to 1.0 nmole g −1 h −1 for EMC. No cleavage of C-Hg bond from MMC was observed by the kidney and liver. The cleavage of PMA was an enzymatic process and the enzyme was located in the nuclear fraction of both liver and kidney. The apparent Michaelis constant and the maximal velocity value for PMA conversion by rat liver slices were 625 μM and 19.2 nmole per g tissue per 2 h, respectively. It is postulated that the PMA molecule is first split at the C-Hg bond to yield benzene and mercuric ion. The cleavage of the EMC molecule appears to be more complex.