Concentration and chemical status of arsenic in the blood of pregnant hamsters during critical embryogenesis. 2. Acute exposure.

We have determined the concentration and chemical composition of arsenic in the blood of pregnant hamsters between 0.2 and 6 hr after an intraperitoneal injection of a teratogenic dose of radiolabeled sodium arsenate on the morning of the eighth day of gestation. Arsenic was present in plasma and red cells 0.20 hr postinjection. The plasma arsenic concentration reached a maximum of 220 mumole/kg blood near 0.5 hr postinjection. Plasma arsenic existed entirely as low-molecular-weight species. Both arsenite and dimethylarsinate (DMA) were present in plasma 0.20 hr postinjection, indicating that arsenate reduction and methylation of arsenic are rapidly initiated. However, the arsenite contribution remained small while the DMA contribution increased with time. Red cell arsenic included macromolecular arsenic (AsP) as well as three low-molecular-weight forms. The contribution of DMA remained small, but arsenite and AsP contributions increased with time. These findings identify the maternal blood concentration and chemical status of arsenic following the administration of a teratogenic dose of arsenate during the period of organogenesis. They could prove useful for predicting the likelihood of a teratogenic outcome in other mammalian species.