[Acceleration of the metabolism of carcinogens in the maternal body and embryos].

Outbred mice on the 19th-21st day of pregnancy were injected intravenously 3,4-benzpyrene (BP) in the dosage of 15 mg/kg or 9,10-dimethyl-1,2-benzanthracene (DMBA) in the dosage of 40 mg/Kg in control groups, and moreover preliminary injected BP (24 hours before) in experimental groups. The BP concentration of embryos and the maternal liver 15 minutes following the injection of the basic dose of the carcinogen in increased dosage of preliminary exposure first would decrease, reach the minimum, in preliminary dosage equal to 0.75 mg/Kg, and then would increase up to values observed in control experiments with the dosage of 30 mg/Kr 7.5-15 mg/Kg, and then it would fall again in the dosage of 30 mg/Kg. The preliminary injection of BP in the dosage of 0.75 mg/Kg produced a sharp fall in the carcinogen concentration in embryos and the maternal organism during the first moment of observation (after 5 minutes), but it failed to influence the rate of subsequent decrease of the substance level. An explanation of the two effects observed is suggested based on the assumption that there exist two enzymatic systems metabolizing BP: one-premanently present in the liver and the other-induced by the carcinogen. The preliminary BP injection did not influence the concentration of DMBA.