Kitawaki J, Inoue S, Tamura T, Yamamoto T, Honjo H, Higashiyama T, Osawa Y, Okada H
Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Japan.
J Steroid Biochem Mol Biol. 1993 Jun;45(6):485-91. doi: 10.1016/0960-0760(93)90163-q.
To clarify whether cigarette smoking during pregnancy causes an organic alteration in placental estrogen producing ability, we determined the catalytic activity of aromatase by the tritiated water assay, and tissue level of aromatase cytochrome P-450 (P-450arom) by the specific enzyme-linked immunosorbent assay, in placental samples from nonsmokers and smokers. As pregnancy progressed, both aromatase activity and P-450arom concentration increased in placentas from nonsmokers and smokers. However, the gradient of the increase was significantly less in heavy smokers (> or = 20 cigarettes a day) than in normal and moderate smokers (< 20 cigarettes a day). At term, the mean aromatase activity and P-450arom concentration in placentas from heavy smokers were significantly lower than in nonsmokers and moderate smokers, while aromatase activity per P-450arom (turnover rate) and the mean placental weight were comparable among the three groups. In contrast, the ratio of aryl hydrocarbon hydroxylase activity to aromatase activity was higher in placentas from heavy smokers. Immunohistochemical studies showed that P-450arom was localized in the cytoplasm of syncytiotrophoblasts of chorionic villi in placentas from both nonsmokers and smokers. These results suggest that the induction of placental P-450arom during gestation is suppressed by maternal smoking, resulting in a reduction in estrogen producing ability, while placental xenobiotic P-450 is induced.
为了阐明孕期吸烟是否会导致胎盘雌激素生成能力发生器质性改变，我们通过氚水测定法测定了芳香化酶的催化活性，并通过特异性酶联免疫吸附测定法测定了非吸烟者和吸烟者胎盘样本中芳香化酶细胞色素P - 450（P - 450arom）的组织水平。随着孕期进展，非吸烟者和吸烟者胎盘中的芳香化酶活性和P - 450arom浓度均升高。然而，重度吸烟者（每天≥20支香烟）的升高梯度明显低于正常吸烟者和中度吸烟者（每天<20支香烟）。足月时，重度吸烟者胎盘的平均芳香化酶活性和P - 450arom浓度显著低于非吸烟者和中度吸烟者，而每P - 450arom的芳香化酶活性（周转率）和胎盘平均重量在三组中相当。相反，重度吸烟者胎盘的芳烃羟化酶活性与芳香化酶活性之比更高。免疫组织化学研究表明，P - 450arom定位于非吸烟者和吸烟者胎盘绒毛膜合体滋养层细胞的细胞质中。这些结果表明，孕期母亲吸烟会抑制胎盘P - 450arom的诱导，导致雌激素生成能力降低，而胎盘外源性P - 450被诱导。
