Distribution and excretion of 74As and 75Se in rats after their simultaneous administration

The exposure of man to an isolated toxic agent in the environment is rather a rare phenomenon. Therefore the study of a combined action of toxic substances is of increasing importance. The excretion and distribution of 74As (500 μg As.kg-1 b.wt.; Na74AsO2) and 75Se (525 μg Se.kg-1 b.wt.; Na275SeO3) were studied in rats after their separate and combined i.v. injections. After the combined administration, urinary and biliary excretions of 75Se and urinary excretion of 74As increased in comparison with that in animals injected the radionuclides separately. The combined administration of 74As and 75Se caused a reduction in the concentration of 75Se in the liver and increased the concentration of 74As in the kidneys. In rats drinking water containing As(III) (0.66 mmol.l-1), Se(IV) (0.13 mmol.l-1) or As(III)+Se(IV) in combination (at the same concentrations) for 7 or 28 days, the excretion and distribution of 74As and 75Se were studied after their combined i.v. injection (at the same concentrations and labelled compounds as mentioned above). Pretreatment with one element or with a combination of both elements significantly modified the distribution and excretion the subsequently administered 74As and 75Se. (author). 3 figs., 5 tabs., 8 refs