Cigarette Smoking: Stimulatory Effect on Metabolism of 3,4-Benzpyrene by Enzymes in Human Placenta

Abstract
The enzymatic hydroxylation of 3,4-benzpyrene was not detected in human placentas obtained after childbirth from nonsmokers, whereas this enzyme activity was present in placentas obtained from individuals who smoked cigarettes. The degree of induction of benzpyrene hydroxylase caused by cigarette smoking varied in different individuals. Treatment of pregnant rats with benzpyrene increased the activity of this hydroxylase in the placenta.