N-Demethylation of levo-α-acetylmethadol by human placental aromatase

Sujal V. Deshmukh, Tatiana Nanovskaya, Gary Hankins, Mahmoud Ahmed

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Levo-α-acetylmethadol (LAAM) is a methadone derivative used to treat the opiate addict. We previously reported on the kinetics for transplacental transfer of LAAM and its levels in the fetal circuit using the technique of dual perfusion of the placental lobule. The aim of this investigation was to identify the enzyme responsible for the biotransformation of LAAM and norLAAM and the metabolites formed in the term human placenta. Placental microsomes exhibited higher activities than the mitochondrial and cytosolic fractions in metabolizing LAAM to norLAAM. None of these subcellular fractions catalyzed the formation of dinorLAAM from either LAAM or norLAAM as determined by HPLC/UV. Evidence obtained from the effects of cytochrome P450 (CYP) inhibitors on the demethylation of LAAM to norLAAM by placental microsomes suggested that CYP 19/aromatase is the major enzyme involved. Out of 10 monoclonal antibodies raised against various CYP isoforms, only that for aromatase caused over 80% inhibition of norLAAM formation. The biotransformation of LAAM to norLAAM exhibited monophasic kinetics with apparent Km and Vmax values of 105±57μM and 86.8±15.6pmolmg -1proteinmin-1, respectively. The kinetic profile determined for a cDNA-expressed CYP 19 metabolism of LAAM to norLAAM was similar to that determined for placental microsomes. Taken together, the above data indicate that CYP 19/aromatase is the enzyme responsible for the N-demethylation of LAAM to norLAAM in term human placentas obtained from healthy pregnant women.

Original languageEnglish (US)
Pages (from-to)885-892
Number of pages8
JournalBiochemical Pharmacology
Volume67
Issue number5
DOIs
StatePublished - Mar 1 2004

Fingerprint

Methadyl Acetate
Aromatase
Microsomes
Biotransformation
Cytochrome P-450 Enzyme System
Placenta
Kinetics
Opiate Alkaloids
Enzymes
Subcellular Fractions
Methadone
Metabolites
Metabolism
Pregnant Women
Protein Isoforms

Keywords

  • Aromatase
  • Human placenta
  • LAAM
  • Metabolism
  • Opiate addict

ASJC Scopus subject areas

  • Pharmacology

Cite this

N-Demethylation of levo-α-acetylmethadol by human placental aromatase. / Deshmukh, Sujal V.; Nanovskaya, Tatiana; Hankins, Gary; Ahmed, Mahmoud.

In: Biochemical Pharmacology, Vol. 67, No. 5, 01.03.2004, p. 885-892.

Research output: Contribution to journalArticle

@article{a38e3fd7c5ad42c0918d92b11c07be78,
title = "N-Demethylation of levo-α-acetylmethadol by human placental aromatase",
abstract = "Levo-α-acetylmethadol (LAAM) is a methadone derivative used to treat the opiate addict. We previously reported on the kinetics for transplacental transfer of LAAM and its levels in the fetal circuit using the technique of dual perfusion of the placental lobule. The aim of this investigation was to identify the enzyme responsible for the biotransformation of LAAM and norLAAM and the metabolites formed in the term human placenta. Placental microsomes exhibited higher activities than the mitochondrial and cytosolic fractions in metabolizing LAAM to norLAAM. None of these subcellular fractions catalyzed the formation of dinorLAAM from either LAAM or norLAAM as determined by HPLC/UV. Evidence obtained from the effects of cytochrome P450 (CYP) inhibitors on the demethylation of LAAM to norLAAM by placental microsomes suggested that CYP 19/aromatase is the major enzyme involved. Out of 10 monoclonal antibodies raised against various CYP isoforms, only that for aromatase caused over 80{\%} inhibition of norLAAM formation. The biotransformation of LAAM to norLAAM exhibited monophasic kinetics with apparent Km and Vmax values of 105±57μM and 86.8±15.6pmolmg -1proteinmin-1, respectively. The kinetic profile determined for a cDNA-expressed CYP 19 metabolism of LAAM to norLAAM was similar to that determined for placental microsomes. Taken together, the above data indicate that CYP 19/aromatase is the enzyme responsible for the N-demethylation of LAAM to norLAAM in term human placentas obtained from healthy pregnant women.",
keywords = "Aromatase, Human placenta, LAAM, Metabolism, Opiate addict",
author = "Deshmukh, {Sujal V.} and Tatiana Nanovskaya and Gary Hankins and Mahmoud Ahmed",
year = "2004",
month = "3",
day = "1",
doi = "10.1016/j.bcp.2003.10.007",
language = "English (US)",
volume = "67",
pages = "885--892",
journal = "Biochemical Pharmacology",
issn = "0006-2952",
publisher = "Elsevier Inc.",
number = "5",

}

TY - JOUR

T1 - N-Demethylation of levo-α-acetylmethadol by human placental aromatase

AU - Deshmukh, Sujal V.

AU - Nanovskaya, Tatiana

AU - Hankins, Gary

AU - Ahmed, Mahmoud

PY - 2004/3/1

Y1 - 2004/3/1

N2 - Levo-α-acetylmethadol (LAAM) is a methadone derivative used to treat the opiate addict. We previously reported on the kinetics for transplacental transfer of LAAM and its levels in the fetal circuit using the technique of dual perfusion of the placental lobule. The aim of this investigation was to identify the enzyme responsible for the biotransformation of LAAM and norLAAM and the metabolites formed in the term human placenta. Placental microsomes exhibited higher activities than the mitochondrial and cytosolic fractions in metabolizing LAAM to norLAAM. None of these subcellular fractions catalyzed the formation of dinorLAAM from either LAAM or norLAAM as determined by HPLC/UV. Evidence obtained from the effects of cytochrome P450 (CYP) inhibitors on the demethylation of LAAM to norLAAM by placental microsomes suggested that CYP 19/aromatase is the major enzyme involved. Out of 10 monoclonal antibodies raised against various CYP isoforms, only that for aromatase caused over 80% inhibition of norLAAM formation. The biotransformation of LAAM to norLAAM exhibited monophasic kinetics with apparent Km and Vmax values of 105±57μM and 86.8±15.6pmolmg -1proteinmin-1, respectively. The kinetic profile determined for a cDNA-expressed CYP 19 metabolism of LAAM to norLAAM was similar to that determined for placental microsomes. Taken together, the above data indicate that CYP 19/aromatase is the enzyme responsible for the N-demethylation of LAAM to norLAAM in term human placentas obtained from healthy pregnant women.

AB - Levo-α-acetylmethadol (LAAM) is a methadone derivative used to treat the opiate addict. We previously reported on the kinetics for transplacental transfer of LAAM and its levels in the fetal circuit using the technique of dual perfusion of the placental lobule. The aim of this investigation was to identify the enzyme responsible for the biotransformation of LAAM and norLAAM and the metabolites formed in the term human placenta. Placental microsomes exhibited higher activities than the mitochondrial and cytosolic fractions in metabolizing LAAM to norLAAM. None of these subcellular fractions catalyzed the formation of dinorLAAM from either LAAM or norLAAM as determined by HPLC/UV. Evidence obtained from the effects of cytochrome P450 (CYP) inhibitors on the demethylation of LAAM to norLAAM by placental microsomes suggested that CYP 19/aromatase is the major enzyme involved. Out of 10 monoclonal antibodies raised against various CYP isoforms, only that for aromatase caused over 80% inhibition of norLAAM formation. The biotransformation of LAAM to norLAAM exhibited monophasic kinetics with apparent Km and Vmax values of 105±57μM and 86.8±15.6pmolmg -1proteinmin-1, respectively. The kinetic profile determined for a cDNA-expressed CYP 19 metabolism of LAAM to norLAAM was similar to that determined for placental microsomes. Taken together, the above data indicate that CYP 19/aromatase is the enzyme responsible for the N-demethylation of LAAM to norLAAM in term human placentas obtained from healthy pregnant women.

KW - Aromatase

KW - Human placenta

KW - LAAM

KW - Metabolism

KW - Opiate addict

UR - http://www.scopus.com/inward/record.url?scp=1042263306&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=1042263306&partnerID=8YFLogxK

U2 - 10.1016/j.bcp.2003.10.007

DO - 10.1016/j.bcp.2003.10.007

M3 - Article

VL - 67

SP - 885

EP - 892

JO - Biochemical Pharmacology

JF - Biochemical Pharmacology

SN - 0006-2952

IS - 5

ER -