Catechol estrogen formation in placental and fetal tissues of humans, macaques, rats and rabbits

Placental and fetal tissues obtained from humans, monkeys, rats and rabbits contained monooxygenases capable of catalyzing the formation of catechol estrogens. Treatments of pregnant rats with phenobarbital, Aroclor 1254, or 3-methylcholanthrene each increased measured rates of catechol estrogen formation in placentas, fetal brains and fetal livers, while other rat tissues exhibited either increased or decreased activity. Treatment of pregnant rabbits with Arocolor 1254 produced an increase in catechol estrogen formation in all fetal tissues studied and in the maternal liver and kidney. Catechol estrogen formation in placental microsomes of macaque monkeys (Macaca arctoides) was generally less than that observed in human placental microsomes. Human placentas obtained from smokers exhibited enhanced catechol estrogen formation and this activity appeared to be highly correlated with placental aryl hydrocarbon hydroxylase activity. The data suggested [a]pyrene in a similar fashion in placental tissues and that the enzyme systems involved may be under similar regulatory control.