Distribution and transplacental transfer of paraquat in rats and guinea-pigs.

Radiolabelled paraquat (bis-N-(14C)methyl-4,4'-bipyridylium chloride) was administered intravenously to pregnant rats and guinea-pigs and examined by the whole body autoradiography method. Male rats were examined for comparison with the same method. The results showed that the radiolabelled compound was rapidly distributed throughout the tissues, with the highest concentrations in the cartilage, kidney, lung, spleen, salivary gland and skin. High concentrations were found in the placenta and throughout the fetuses 0.5 hr after the administration.