Interaction of zinc, methionine or their combination with lead at gastrointestinal or post-absorptive level in rats.

The ability of zinc, methionine or their combination given by gavage to prevent or treat experimental oral lead intoxication in rats was investigated. Simultaneous oral supplementation with zinc plus methionine was found to be most effective in reducing lead induced inhibition of delta-aminolevulinic acid dehydratase (ALAD) activity in blood, elevation of urinary delta-aminolevulinic acid (ALA) excretion and in enhancing the hepatic glutathione (GSH) contents. The combination was also most effective in reducing the accumulation of lead in blood, liver and kidney compared to zinc or methionine alone. Prevention was more effective than treatment after lead exposure which may be caused by a decrease in the absorption of lead in the gastrointestinal tract in the presence of zinc and/or methionine.