Whole-body retention, excretion and metabolism of [74As]arsenic acid in the hamster.

In order to assess the whole-body retention, excretion and metabolism of inorganic arsenic, male and female hamsters were given either a single oral or i.v. dose of 74As (congruent to 33' microCi/hamster; 0.01 micrograms arsenic/hamster) as arsenic acid. 74As radioactivity was measured in the whole body, urine and feces for up to 35 days. 24-h samples of urine were analyzed for arsenic metabolites. For the i.v. dosed hamsters, the half-period of elimination for the first component (65% of the dose) was 0.40 days; the second component (35% of the dose) had a half-period of 4.5 days. For the orally dosed hamsters, the half-period of elimination for the first component (98% of the dose) was 0.29 days; the second component (2% of the dose) had a half-period of 3.8 days. Differences in the percent of dose excreted between oral and i.v. dosed hamsters appeared to be due to the increased fecal excretion of arsenic (70%) in the orally dosed hamsters as compared to the i.v.v dosed hamsters (6%). No statistically significant differences between the i.v. and oral treatments were found in the half-periods of elimination for either of the 2 components. Analysis of the urine for metabolites revealed arsenic was present as dimethylarsinic acid and inorganic arsenic.