[Effect of selenium on transplacental carcinogenesis]

The effect of prolonged postnatal treatment with sodium selenite dissolved in drinking water upon transplacental carcinogenicity of N-ethyl-N-nitrosourea (ENU) was studied in noninbred albino rats and that of urethan in noninbred albino mice. Selenium treatment (4 ppm) did not produce a significant influence upon the development of neurogenic tumors and mesenchymal kidney tumors induced by transplacental administration of ENU (75 mg/kg) in rat offsprings. On the contrary, in mice progeny, selenium (2 ppm) showed an inhibitory effect upon the development of lung adenomas induced by transplacental administration of urethan (1 g/kg). However, it decreased significantly tumor multiplicity only. Inhibition of non-epithelial tumor development by selenium treatment seems to be less effective at the stage of carcinogenesis promotion.