[Influence of the polypeptide preparations cortexin and encephalin on the transplacental carcinogenic effect of N-nitroso-N-ethylurea in rats].

The polypeptide preparations cortexin and encephalin from grey and white substances of the cattle brain injected in the postnatal period are studied for their effect on the development of the nervous system and kidney tumours in rats induced transplacentally by N-nitroso-N-ethylurea. The two preparations decreased both the incidence and multiplicity of the brain tumours. It is supposed that the anticarcinogenic effect of these preparations is due to their normalizing action on the differentiation and proliferation of the brain glia cells.