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Drug metabolism by placenta
Author(s) -
Juchau Mont R.,
Pedersen Mark G.,
Fantel Alan G.,
Shepard Thomas H.
Publication year - 1973
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/cpt1973144part2673
Subject(s) - hydroxylation , chemistry , placenta , xenobiotic , enzyme , drug metabolism , mixed function oxidase , metabolism , biochemistry , catalysis , microsome , fetus , biology , pregnancy , genetics
Measurable catalysis of mixed‐function oxidations of foreign organic compounds in human placental tissues appears to occur only with a limited number of substrates including 3,4‐benzpyrene, 3'‐methyl‐4‐monomethylaminoazobenzene, and N‐monomethylaniline. Evidence now indicates that mixed‐function oxidations of the classical “type 1” drug substrates (the hepatic biotramformations of which are markedly accelerated following pretreatment with phenobarbital and decreased or unchanged following pretreatment with polycyclic aromatic hydrocarbons) occur at extremely low or negligible rates in human placentas. Xenobiotic monooxygenation reactions that are induced strongly by exposure to polycyclic aromatic hydrocarbons appear more likely to be catalyzed by placental enzyme systems, although exceptions exist and sufficient studies to warrant broad generalizations have not yet been carried out. Enzymes that catalyze the ω‐oxidation of 14 C‐laurate could not be detected in human placentas. No relationships between the highly active human placental aromatase system and placental drug hydroxylation reactions were found, whereas an inverse correlation between specific activities of the placental aryl hydrocarbon hydroxylase and cholesterol side‐chain oxidase may exist.