title: Identification of CYP3A7 for glyburide metabolism in human fetal livers.
abstract: Glyburide is commonly prescribed for the treatment of gestational diabetes mellitus; however, fetal exposure to glyburide is not well understood and may have short- and long-term consequences for the health of the child. Glyburide can cross the placenta; fetal concentrations at term are nearly comparable to maternal levels. Whether or not glyburide is metabolized in the fetus and by what mechanisms has yet to be determined. In this study, we determined the kinetic parameters for glyburide depletion by CYP3A isoenzymes; characterized glyburide metabolism by human fetal liver tissues collected during the first or early second trimester of pregnancy; and identified the major enzyme responsible for glyburide metabolism in human fetal livers. CYP3A4 had the highest metabolic capacity towards glyburide, followed by CYP3A7 and CYP3A5 (Clint,u=37.1, 13.0, and 8.7ml/min/nmol P450, respectively). M5 was the predominant metabolite generated by CYP3A7 and human fetal liver microsomes (HFLMs) with approximately 96% relative abundance. M5 was also the dominant metabolite generated by CYP3A4, CYP3A5, and adult liver microsomes; however, M1-M4 were also present, with up to 15% relative abundance. CYP3A7 protein levels in HFLMs were highly correlated with glyburide Clint, 16α-OH DHEA formation, and 4'-OH midazolam formation. Likewise, glyburide Clint was highly correlated with 16α-OH DHEA formation. Fetal demographics as well as CYP3A5 and CYP3A7 genotype did not alter CYP3A7 protein levels or glyburide Clint. These results indicate that human fetal livers metabolize glyburide predominantly to M5 and that CYP3A7 is the major enzyme responsible for glyburide metabolism in human fetal livers.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: dshust@uw.edu.
authors.forename: Diana L
authors.initials: DL
authors.lastname: Shuster
authors.affiliation: Department of Pharmacy, University of Washington, Box 357630, Seattle, Washington 98195, USA. Electronic address: lrisler@uw.edu.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Risler
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: bhagwat@uw.edu.
authors.forename: Bhagwat
authors.initials: B
authors.lastname: Prasad
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: jcalamia@uw.edu.
authors.forename: Justina C
authors.initials: JC
authors.lastname: Calamia
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: jennav2@uw.edu.
authors.forename: Jenna L
authors.initials: JL
authors.lastname: Voellinger
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: edkelly@uw.edu.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Kelly
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: jash@uw.edu.
authors.forename: Jashvant D
authors.initials: JD
authors.lastname: Unadkat
authors.affiliation: Department of Pharmacy, University of Washington, Box 357630, Seattle, Washington 98195, USA; Department of Obstetrics and Gynecology, University of Washington, Box 356460, Seattle, Washington 98195, USA. Electronic address: mhebert@uw.edu.
authors.forename: Mary F
authors.initials: MF
authors.lastname: Hebert
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA; Department of Pharmacy, University of Washington, Box 357630, Seattle, Washington 98195, USA. Electronic address: ds@uw.edu.
authors.forename: Danny D
authors.initials: DD
authors.lastname: Shen
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: thummel@uw.edu.
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Thummel
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, University of Washington, Box 357610, Seattle, WA 98195, USA. Electronic address: qmao@uw.edu.
authors.forename: Qingcheng
authors.initials: Q
authors.lastname: Mao
mesh_terms: D000595:Amino Acid Sequence; D001189:Aryl Hydrocarbon Hydroxylases / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D051544:Cytochrome P-450 CYP3A; D005905:Glyburide / Q000378:metabolism* / Q000493:pharmacokinetics; D006801:Humans; D007004:Hypoglycemic Agents / Q000378:metabolism* / Q000493:pharmacokinetics; D008099:Liver / Q000196:embryology* / Q000201:enzymology / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D053719:Tandem Mass Spectrometry
chemical_list: D007004:Hypoglycemic Agents; D001189:Aryl Hydrocarbon Hydroxylases; C103123:CYP3A7 protein, human; D051544:Cytochrome P-450 CYP3A; D005905:Glyburide
keywords: 16α-hydroxydehydroepiandrosterone (PubChem CID: 102030); 1′-Hydroxymidazolam (PubChem CID: 107917); 4′-Hydroxymidazolam (Pubchem CID: 124449); CYP3A7; Dehydroepiandrosterone (PubChem CID: 5881); Fetal metabolism; Gestational diabetes mellitus; Glyburide; Glyburide (PubChem CID: 3488); Human fetal livers; Midazolam (PubChem CID: 4192)