Effect of maternal cigarette smoking on 3,4-benzpyrene and N-methylaniline metabolism in human fetal liver and placenta

Abstract

The effect of maternal cigarette smoking on the metabolism of 3,4-benzpyrene (BP) and N-methylaniline (MA) was studied in human fetal liver and placenta. Maternal cigarette smoking apparently had no effect on fetal hepatic drug metabolism. Placentas from smokers, unlike those from nonsmokers, were able to metabolize BP both in the first half of pregnancy and at term. The critical duration of gestation for the appearance of the effect of cigarette smoking seemed to be about 10–11 wk. Metabolism of MA by placental homogenates was very low during the pregnancy, and maternal cigarette smoking had no effect on it. No correlation was established between the level of BP hydroxylase activity in the fetal liver and the level of BP hydroxylase activity in the placenta of the same mother. The fetal hepatic and placental BP hydroxylase systems were shown to differ in their response to maternal cigarette smoking, their subcellular location and their kinetic characteristics.