Intracellular distribution and chemical forms of arsenic in rabbits exposed to arsenate.

Inhibition of the methylation of arsenic in rabbits by ip injection of periodate-oxidized adenosine (PAD) prior to an iv injection of 74As-arsenate (AsV; 0.4 mg As/kg body wt) caused a marked increase in the retention of 74As in both the cellular organelles and the soluble fractions of liver and kidney. One day after exposure, almost 30% of the arsenic in the liver and about 40% of the arsenic in the kidney was recovered in the nuclear fraction. In the liver nuclei, the inhibition of the methylation increased the 74As content of the insoluble fraction and most of this arsenic was protein-bound. The major part of the soluble intranuclear 74As was in the form of AsIII, formed by reduction of the administered AsV. In the liver, PAD also caused a pronounced increase in the 74As content of the microsomal fraction. In the kidneys, where most of the arsenic was present as AsV, there was a marked accumulation of arsenic in the mitochondria.