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Comparison of the O‐dealkylation of 7‐ethoxycoumarin and the hydroxylation of benzo [a] pyrene in human placenta
Author(s) -
Jacobson M.,
Levin W.,
Poppers P. J.,
Wood A. W.,
Conney A. H.
Publication year - 1974
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt1974164701
Subject(s) - hydroxylation , chemistry , pyrene , placenta , coumarin , in vitro , benzopyrene , fetus , metabolism , endocrinology , carcinogen , biochemistry , benzo(a)pyrene , enzyme , medicine , pharmacology , pregnancy , biology , organic chemistry , genetics
A highly sensitive method is described for measuring the in vitro metabolism of 7‐ethoxycoumarin or coumarin to 7‐hydroxycoumarin. This method was used to measure the O‐dealkylation of 7‐ethoxycoumarin and the hydroxylation of coumarin by placentas from 12 nonsmokers or from 12 women who smoked cigarettes. Although an induced level of benzo[a]pyrene (BP) hydroxylase activity was found in each placenta obtained from women who smoked cigarettes during pregnancy, 7‐ethoxycoumarin O‐dealkylase activity was induced (about 2 fold) only in placentas whose BP hydroxylase activity was markedly induced (50 to 100 fold). These results indicate that ethoxycoumarin dealkylase activity parallels BP hydroxylase activity in human placenta only in individuals with markedly induced BP hydroxylase activity. No detectable hydroxylation of coumarin in the 7‐position was observed in placental homogenates from nonsmokers 0., from women who smoked cigarettes.