Protective effect of molybdenum on the acute toxicity of mercuric chloride. II.

Abstract

The protective mechanism of Na2MoO4 against the acute toxicity of HgCl2 was studied by investigating the subcellular distributions of Hg and Mo in the liver and kidney of rats treated with Na2MoO4 and/or HgCl2, and by performing Sephadex G-75 gel chromatography of the liver and kidney cytosol obtained from these groups. The rats given HgCl2 (0.03 mmol/kg, once, s.c.) after pretreatment with Na2MoO4 (1.24 mmol/kg, once a day for 3 days, i.p.) have decreased Hg contents in the liver mitochondrial and microsomal fractions and in the renal nuclear fraction, in comparison with those of rats given HgCl2 alone. The Hg content in the renal cytosol of this group was increased in comparison with that of the rats given HgCl2 alone. A gel filtration study showed that the increase in Hg content of the renal cytosol of the rats pretreated with Na2MoO4 was associated with an increase in the metal content in the metallothionein-like fraction. Apparently Mo alleviated the acute HgCl2 toxicity not only by reducing the Hg contents in the mitochondrial and microsomal fractions of liver and in the nuclear fraction of kidney, but also by enhancing the retention of Hg in the renal metallothionein-like fraction.