Metabolic characteristics and enflurane defluorination of cytochrome P450-dependent monooxygenases in human hepatocellular carcinoma

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Abstract

Background: Xenobiotic metabolism and defluorination capacity of microsomal monooxygenases were investigated in vitro through the surgical specimens of liver resected from patients with hepatocellular carcinoma and patients of extrahepatic pathology as control. Methods : In microsomes of hepatocellular carcinoma tissues, the activities of cytochrome P450-dependent monooxygenase isozymes 1A1, 2B1, and 2E1 were evaluated in vitro by reacting with the specific marker substrates benzo(a)pyrene, benzphetamine and aniline, respectively, in the generating incubation system. The distant normal liver tissues and tissues from control patients with extrahepatic lesion were also investigated for comparison. The ability of enflurane bined electrode for detection of free fluoride ion production. Results: Concentrations of P450 total content, cytochrome b5, and NADPH-cytochrome c reductase showed parallel and marked reduction in tumor tissues when compared with its distant normal regions or normal livers. The monooxygenase functions displayed significant decreases within the tumor tissues as benzo(a)pyrene hydroxylation ≥ benzphetamine demethylation > aniline hydroxylation in magnitude. Defluorination of enflurane also markedly decreased in tumor tissues comparing with normal livers. Conclusions: These marked reductions in the compositions and in vitro metabolic activities, including defluorination of anesthetics, in the cytochrome P450-dependent monooxygenases within the tumor tissues characterize the unique pattern of xenobiotic metabolism in patients with hepatocellular carcinoma.

Original languageEnglish
Pages (from-to)7-14
Number of pages8
JournalActa Anaesthesiologica Sinica
Volume35
Issue number1
Publication statusPublished - 1997
Externally publishedYes

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Enflurane
Mixed Function Oxygenases
Cytochrome P-450 Enzyme System
Hepatocellular Carcinoma
Benzphetamine
Benzo(a)pyrene
Liver
Xenobiotics
Hydroxylation
Neoplasms
Aryl Hydrocarbon Hydroxylases
Cytochromes b5
NADPH-Ferrihemoprotein Reductase
Microsomes
Fluorides
Isoenzymes
Anesthetics
Electrodes
Ions
Pathology

Keywords

  • Carcinoma: Hepatocellular
  • Enzymes: Cytochrome p450 monooxygenases
  • Metabolism: Defluorination

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

Cite this

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title = "Metabolic characteristics and enflurane defluorination of cytochrome P450-dependent monooxygenases in human hepatocellular carcinoma",
abstract = "Background: Xenobiotic metabolism and defluorination capacity of microsomal monooxygenases were investigated in vitro through the surgical specimens of liver resected from patients with hepatocellular carcinoma and patients of extrahepatic pathology as control. Methods : In microsomes of hepatocellular carcinoma tissues, the activities of cytochrome P450-dependent monooxygenase isozymes 1A1, 2B1, and 2E1 were evaluated in vitro by reacting with the specific marker substrates benzo(a)pyrene, benzphetamine and aniline, respectively, in the generating incubation system. The distant normal liver tissues and tissues from control patients with extrahepatic lesion were also investigated for comparison. The ability of enflurane bined electrode for detection of free fluoride ion production. Results: Concentrations of P450 total content, cytochrome b5, and NADPH-cytochrome c reductase showed parallel and marked reduction in tumor tissues when compared with its distant normal regions or normal livers. The monooxygenase functions displayed significant decreases within the tumor tissues as benzo(a)pyrene hydroxylation ≥ benzphetamine demethylation > aniline hydroxylation in magnitude. Defluorination of enflurane also markedly decreased in tumor tissues comparing with normal livers. Conclusions: These marked reductions in the compositions and in vitro metabolic activities, including defluorination of anesthetics, in the cytochrome P450-dependent monooxygenases within the tumor tissues characterize the unique pattern of xenobiotic metabolism in patients with hepatocellular carcinoma.",
keywords = "Carcinoma: Hepatocellular, Enzymes: Cytochrome p450 monooxygenases, Metabolism: Defluorination",
author = "Ta-Liang Chen",
year = "1997",
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T1 - Metabolic characteristics and enflurane defluorination of cytochrome P450-dependent monooxygenases in human hepatocellular carcinoma

AU - Chen, Ta-Liang

PY - 1997

Y1 - 1997

N2 - Background: Xenobiotic metabolism and defluorination capacity of microsomal monooxygenases were investigated in vitro through the surgical specimens of liver resected from patients with hepatocellular carcinoma and patients of extrahepatic pathology as control. Methods : In microsomes of hepatocellular carcinoma tissues, the activities of cytochrome P450-dependent monooxygenase isozymes 1A1, 2B1, and 2E1 were evaluated in vitro by reacting with the specific marker substrates benzo(a)pyrene, benzphetamine and aniline, respectively, in the generating incubation system. The distant normal liver tissues and tissues from control patients with extrahepatic lesion were also investigated for comparison. The ability of enflurane bined electrode for detection of free fluoride ion production. Results: Concentrations of P450 total content, cytochrome b5, and NADPH-cytochrome c reductase showed parallel and marked reduction in tumor tissues when compared with its distant normal regions or normal livers. The monooxygenase functions displayed significant decreases within the tumor tissues as benzo(a)pyrene hydroxylation ≥ benzphetamine demethylation > aniline hydroxylation in magnitude. Defluorination of enflurane also markedly decreased in tumor tissues comparing with normal livers. Conclusions: These marked reductions in the compositions and in vitro metabolic activities, including defluorination of anesthetics, in the cytochrome P450-dependent monooxygenases within the tumor tissues characterize the unique pattern of xenobiotic metabolism in patients with hepatocellular carcinoma.

AB - Background: Xenobiotic metabolism and defluorination capacity of microsomal monooxygenases were investigated in vitro through the surgical specimens of liver resected from patients with hepatocellular carcinoma and patients of extrahepatic pathology as control. Methods : In microsomes of hepatocellular carcinoma tissues, the activities of cytochrome P450-dependent monooxygenase isozymes 1A1, 2B1, and 2E1 were evaluated in vitro by reacting with the specific marker substrates benzo(a)pyrene, benzphetamine and aniline, respectively, in the generating incubation system. The distant normal liver tissues and tissues from control patients with extrahepatic lesion were also investigated for comparison. The ability of enflurane bined electrode for detection of free fluoride ion production. Results: Concentrations of P450 total content, cytochrome b5, and NADPH-cytochrome c reductase showed parallel and marked reduction in tumor tissues when compared with its distant normal regions or normal livers. The monooxygenase functions displayed significant decreases within the tumor tissues as benzo(a)pyrene hydroxylation ≥ benzphetamine demethylation > aniline hydroxylation in magnitude. Defluorination of enflurane also markedly decreased in tumor tissues comparing with normal livers. Conclusions: These marked reductions in the compositions and in vitro metabolic activities, including defluorination of anesthetics, in the cytochrome P450-dependent monooxygenases within the tumor tissues characterize the unique pattern of xenobiotic metabolism in patients with hepatocellular carcinoma.

KW - Carcinoma: Hepatocellular

KW - Enzymes: Cytochrome p450 monooxygenases

KW - Metabolism: Defluorination

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