Characteristic Effects of L-Methionine on Tissue Distribution of Methylmercury in Mice

Abstract

The effects of L-methionine (Met) on tissue distribution of methylmercury (MeHg) in mice were investigated and compared to those of other amino acids and amino acid analogues to determine whether Met could play special roles in distribution of MeHg. Three hr after the injection with MeHg-L-cysteine (Cys) (10 μmol/kg each), brain Hg concentration was suppressed by a co-injection with Met, L-phenylalanine (Phe), L-leucine (Leu) or 2-amino-2-norbornane-carboxylic acid (BCH), although the concentration was not affected by that with L-serine, α-aminoisobutyric acid or α-(methylamino)isobutyric acid. Hg concentration in liver was enhanced but that in the kidney was suppressed only by the co-injection with Met. Hg concentrations in blood and plasma were suppressed only by Met at least within 2 hr, but these differences disappeared at 3 hr. These results suggest that Met plays important and special roles in tissue distribution of MeHg in mice, at least in the liver and kidney, although MeHg distribution in the brain is similarly affected by not only Met but also other compounds such as Phe, Leu and BCH.