title: [Mechanism of transplacental penetration of N-nitrosodimethylamine into rat and mouse fetuses].
abstract: The authors have studied the time course of changes in N-nitrosodimethylamine (NDMA) concentration in the blood, liver, muscle tissue and embryo of pregnant rats and mice after its intravenous injection in a dose of 50 mg/kg. In the parent organism, the maximal concentration was attained immediately after injection as shown by the measurements made 5 minutes after and then decreased according to the exponential law, with that decrease occurring far rapidly in mice than in rats. In the embryo, the maximal concentration attainment was 30-60 minutes as delayed. The concentration of NDMA in the embryo and tissues of the parent organism ascended linearly up to a definite level as the dose was raised (blood concentration) whereupon its increase became slower and even ceased which forms the basis for an assumption that the carcinogenic substance penetrates via the placenta and cell membranes according to the laws of transport with the aid of carriers.
mesh_terms: D000818:Animals; D004128:Dimethylnitrosamine / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005333:Fetus / Q000187:drug effects* / Q000378:metabolism; D008431:Maternal-Fetal Exchange / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D010920:Placenta / Q000187:drug effects* / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D004128:Dimethylnitrosamine
vernacular_title: O mekhanizme transplatsentarnogo proniknoveniia N-nitrozodimetilamina v plod krys i mysheĭ.