[Effect of tocopherol, phenformin and thymus and pineal polypeptide factors on the transplacental carcinogenic effect of N-nitroso-N-ethylurea in rats].

The study was concerned with the influence of postnatal treatment with antioxidant tocopherol, antidiabetic drug phenformin and low-molecular polypeptide factors of the thymus (thymalin) and pineal gland (epithalamin) on transplacental carcinogenicity of low-dose (7.5 mg/kg body weight, 3.2% of LD 50) N-ethyl-N-nitrosourea (ENU) in rats. Transplacental exposure to ENU was followed mainly by the development of brain tumors. Tumors of the spinal cord, peripheral nervous system and kidney were observed much more rarely. Treatment with tocopherol, thymalin or epithalamin did not significantly influence the transplacental carcinogenicity of ENU, whereas application of phenformin was followed by a decreased incidence of brain tumors.