Protective effect of molybdenum on the acute toxicity of mercuric chloride

The effect of molybdenum on the acute toxicity of mercuric chloride was examined. Rats that were given mercuric chloride alone (0.03 mmol/kg, once, sc) all died within 2 days after treatment. However, rats pretreated with sodium molybdate (1.24 mmol/kg, once a day for 3 days, ip) all survived for 6 days after administration of the same dose of mercuric chloride. The pretreatment with molybdenum decreased the mercury content in the liver, kidney, and spleen, but the molybdenum content in the liver, kidney, and large intestine were increased in comparison with those of the rats given molybdenum alone. Moreover, pretreatment with molybdenum caused polyuria in contrast with anuria in rats given mercuric chloride alone. These data suggest that a protective mechanism of molybdenum is the ability of this metal to decrease the mercury content in the liver, kidney, and spleen by enhancement of urinary excretion of mercury.