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Antipyrine as a probe for human oxidative drug metabolism: identification of the cytochrome P450 enzymes catalyzing 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation.
Clin Pharmacol Ther. 1996 Jun; 59(6):613-23.CP

Abstract

BACKGROUND AND OBJECTIVE

Antipyrine has been widely used as a probe drug for human oxidative drug metabolism. To evaluate the role of antipyrine as a model drug, we have identified the cytochrome P450 enzymes involved in 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation.

METHODS

We used the following methods for this study: (1) determination of enzyme kinetics for antipyrine metabolite formation in human liver microsomes, (2) inhibition studies with antibodies and inhibitors, and (3) formation of metabolites by stable expressed human P450 enzymes.

RESULTS

Antipyrine biotransformation could be described by Michaelis-Menten kinetics: norantipyrine: maximum rate of metabolite formation (Vmax), 0.91 +/- 0.04 nmol . mg-1 . min-1; Michaelis-Menten constant (Km), 19.0 +/- 0.8 mmol/L; 4-hydroxyantipyrine: Vmax, 1.54 +/- 0.08 nmol . mg-1 . min-1;Km,39.6 +/- 2.5 mmol/L. Antibodies against CYP3A4 inhibited the formation of 4-hydroxyantipyrine by 25% to 65%. LKM-2 antibodies (anti-CYP2C) caused a 75% to 100% inhibition of norantipyrine and a 58% to 80% inhibition of 3-hydroxymethylantipyrine formation. Sulfaphenazole inhibited the formation of 3-hydroxymethylantipyrine and norantipyrine by about 50%. Furafylline and fluvoxamine inhibited norantipyrine, 4-hydroxyantipyrine, and 3-hydroxymethylantipyrine formation by about 30%, 30%, and 50%, respectively. Ketoconazole reduced formation of norantipyrine, 3-hydroxymethylantipyrine, and 4-hydroxyantipyrine by up to 80%. Formation in stable expressed enzymes indicated involvement of CYP1A2, CYP2B6, CYP2C, and CYP3A4 in metabolite formation.

CONCLUSION

Antipyrine metabolites are formed by at least six hepatic cytochrome P450 enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C18, and CYP3A4). 4-Hydroxylation is mainly catalyzed by CYP3A4 and, to a lesser extent, by CYP1A2. The CYP2C subfamily contains the predominant enzymes for norantipyrine formation, and CYP1A2 is also involved. Formation of 3-hydroxymethylantipyrine is mediated by CYP1A2 and CYP2C9. Because several cytochrome P450 enzymes are involved in the formation of each metabolite, antipyrine is not well suited as a probe for distinct human cytochrome P450 enzymes.

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Authors+Show Affiliations

Engel G
Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, Germany.
Hofmann U
No affiliation info available
Heidemann H
No affiliation info available
Cosme J
No affiliation info available
Eichelbaum M
No affiliation info available

MeSH

Anti-Inflammatory Agents, Non-SteroidalAntipyrineAutoantibodiesBiotransformationCatalysisCytochrome P-450 Enzyme InhibitorsCytochrome P-450 Enzyme SystemEdaravoneGas Chromatography-Mass SpectrometryHumansMicrosomes, Liver

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8681486

Citation

Engel, G, et al. "Antipyrine as a Probe for Human Oxidative Drug Metabolism: Identification of the Cytochrome P450 Enzymes Catalyzing 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and Norantipyrine Formation." Clinical Pharmacology and Therapeutics, vol. 59, no. 6, 1996, pp. 613-23.
Engel G, Hofmann U, Heidemann H, et al. Antipyrine as a probe for human oxidative drug metabolism: identification of the cytochrome P450 enzymes catalyzing 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation. Clin Pharmacol Ther. 1996;59(6):613-23.
Engel, G., Hofmann, U., Heidemann, H., Cosme, J., & Eichelbaum, M. (1996). Antipyrine as a probe for human oxidative drug metabolism: identification of the cytochrome P450 enzymes catalyzing 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation. Clinical Pharmacology and Therapeutics, 59(6), 613-23.
Engel G, et al. Antipyrine as a Probe for Human Oxidative Drug Metabolism: Identification of the Cytochrome P450 Enzymes Catalyzing 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and Norantipyrine Formation. Clin Pharmacol Ther. 1996;59(6):613-23. PubMed PMID: 8681486.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Antipyrine as a probe for human oxidative drug metabolism: identification of the cytochrome P450 enzymes catalyzing 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation. AU - Engel,G, AU - Hofmann,U, AU - Heidemann,H, AU - Cosme,J, AU - Eichelbaum,M, PY - 1996/6/1/pubmed PY - 1996/6/1/medline PY - 1996/6/1/entrez SP - 613 EP - 23 JF - Clinical pharmacology and therapeutics JO - Clin Pharmacol Ther VL - 59 IS - 6 N2 - BACKGROUND AND OBJECTIVE: Antipyrine has been widely used as a probe drug for human oxidative drug metabolism. To evaluate the role of antipyrine as a model drug, we have identified the cytochrome P450 enzymes involved in 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation. METHODS: We used the following methods for this study: (1) determination of enzyme kinetics for antipyrine metabolite formation in human liver microsomes, (2) inhibition studies with antibodies and inhibitors, and (3) formation of metabolites by stable expressed human P450 enzymes. RESULTS: Antipyrine biotransformation could be described by Michaelis-Menten kinetics: norantipyrine: maximum rate of metabolite formation (Vmax), 0.91 +/- 0.04 nmol . mg-1 . min-1; Michaelis-Menten constant (Km), 19.0 +/- 0.8 mmol/L; 4-hydroxyantipyrine: Vmax, 1.54 +/- 0.08 nmol . mg-1 . min-1;Km,39.6 +/- 2.5 mmol/L. Antibodies against CYP3A4 inhibited the formation of 4-hydroxyantipyrine by 25% to 65%. LKM-2 antibodies (anti-CYP2C) caused a 75% to 100% inhibition of norantipyrine and a 58% to 80% inhibition of 3-hydroxymethylantipyrine formation. Sulfaphenazole inhibited the formation of 3-hydroxymethylantipyrine and norantipyrine by about 50%. Furafylline and fluvoxamine inhibited norantipyrine, 4-hydroxyantipyrine, and 3-hydroxymethylantipyrine formation by about 30%, 30%, and 50%, respectively. Ketoconazole reduced formation of norantipyrine, 3-hydroxymethylantipyrine, and 4-hydroxyantipyrine by up to 80%. Formation in stable expressed enzymes indicated involvement of CYP1A2, CYP2B6, CYP2C, and CYP3A4 in metabolite formation. CONCLUSION: Antipyrine metabolites are formed by at least six hepatic cytochrome P450 enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C18, and CYP3A4). 4-Hydroxylation is mainly catalyzed by CYP3A4 and, to a lesser extent, by CYP1A2. The CYP2C subfamily contains the predominant enzymes for norantipyrine formation, and CYP1A2 is also involved. Formation of 3-hydroxymethylantipyrine is mediated by CYP1A2 and CYP2C9. Because several cytochrome P450 enzymes are involved in the formation of each metabolite, antipyrine is not well suited as a probe for distinct human cytochrome P450 enzymes. SN - 0009-9236 UR - https://www.unboundmedicine.com/medline/citation/8681486/Antipyrine_as_a_probe_for_human_oxidative_drug_metabolism:_identification_of_the_cytochrome_P450_enzymes_catalyzing_4_hydroxyantipyrine_3_hydroxymethylantipyrine_and_norantipyrine_formation_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0009-9236&date=1996&volume=59&issue=6&spage=613 DB - PRIME DP - Unbound Medicine ER -
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