Identification of canine cytochrome P-450s (CYPs) metabolizing the tramadol (+)-M1 and (+)-M2 metabolites to the tramadol (+)-M5 metabolite in dog liver microsomes

Tania E Perez Jimenez; Katrina L Mealey; Darren Schnider; Tamara L Grubb; Stephen A Greene; Michael H Court

doi:10.1111/jvp.12706

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Identification of canine cytochrome P-450s (CYPs) metabolizing the tramadol (+)-M1 and (+)-M2 metabolites to the tramadol (+)-M5 metabolite in dog liver microsomes

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Identification of canine cytochrome P-450s (CYPs) metabolizing the tramadol (+)-M1 and (+)-M2 metabolites to the tramadol (+)-M5 metabolite in dog liver microsomes

Tania E Perez Jimenez, Katrina L Mealey, Darren Schnider, Tamara L Grubb, Stephen A Greene and Michael H Court

Journal of veterinary pharmacology and therapeutics, Vol.41(6), pp.815-824

12/2018

DOI: https://doi.org/10.1111/jvp.12706

Handle:

https://hdl.handle.net/2376/115015

PMCID: PMC6214715

PMID: 30113702

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Abstract

Cytochrome P450 Family 2 - antagonists & inhibitors

Steroid Hydroxylases - metabolism

Aryl Hydrocarbon Hydroxylases - antagonists & inhibitors

Species Specificity

Humans

Microsomes, Liver - metabolism

Aryl Hydrocarbon Hydroxylases - genetics

Enzyme Inhibitors - pharmacology

Dogs - metabolism

Male

Tramadol - metabolism

Aryl Hydrocarbon Hydroxylases - metabolism

Gene Expression Regulation - drug effects

Animals

Cats - metabolism

Cytochrome P450 Family 2 - metabolism

Steroid Hydroxylases - antagonists & inhibitors

Cytochrome P450 Family 2 - genetics

Female

Analgesics, Opioid - metabolism

Steroid Hydroxylases - genetics

We previously showed that (+)-tramadol is metabolized in dog liver to (+)-M1 exclusively by CYP2D15 and to (+)-M2 by multiple CYPs, but primarily CYP2B11. However, (+)-M1 and (+)-M2 are further metabolized in dogs to (+)-M5, which is the major metabolite found in dog plasma and urine. In this study, we identified canine CYPs involved in metabolizing (+)-M1 and (+)-M2 using recombinant enzymes, untreated dog liver microsomes (DLMs), inhibitor-treated DLMs, and DLMs from CYP inducer-treated dogs. A canine P-glycoprotein expressing cell line was also used to evaluate whether (+)-tramadol, (+)-M1, (+)-M2, or (+)-M5 are substrates of canine P-glycoprotein, thereby limiting their distribution into the central nervous system. (+)-M5 was largely formed from (+)-M1 by recombinant CYP2C21 with minor contributions from CYP2C41 and CYP2B11. (+)-M5 formation in DLMs from (+)-M1 was potently inhibited by sulfaphenazole (CYP2C inhibitor) and chloramphenicol (CYP2B11 inhibitor) and was greatly increased in DLMs from phenobarbital-treated dogs. (+)-M5 was formed from (+)-M2 predominantly by CYP2D15. (+)-M5 formation from (+)-M1 in DLMs was potently inhibited by quinidine (CYP2D inhibitor) but had only a minor impact from all CYP inducers tested. Intrinsic clearance estimates showed over 50 times higher values for (+)-M5 formation from (+)-M2 compared with (+)-M1 in DLMs. This was largely attributed to the higher enzyme affinity (lower Km) for (+)-M2 compared with (+)-M1 as substrate. (+)-tramadol, (+)-M1, (+)-M2, or (+)-M5 were not p-glycoprotein substrates. This study provides a clearer picture of the role of individual CYPs in the complex metabolism of tramadol in dogs.

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Title: Identification of canine cytochrome P-450s (CYPs) metabolizing the tramadol (+)-M1 and (+)-M2 metabolites to the tramadol (+)-M5 metabolite in dog liver microsomes
Creators: Tania E Perez Jimenez - Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, Pharmacogenomics Laboratory, Washington State University College of Veterinary Medicine, Pullman, Washington
Katrina L Mealey - Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, Pharmacogenomics Laboratory, Washington State University College of Veterinary Medicine, Pullman, Washington
Darren Schnider - Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, Pharmacogenomics Laboratory, Washington State University College of Veterinary Medicine, Pullman, Washington
Tamara L Grubb - Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, Pharmacogenomics Laboratory, Washington State University College of Veterinary Medicine, Pullman, Washington
Stephen A Greene - Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, Pharmacogenomics Laboratory, Washington State University College of Veterinary Medicine, Pullman, Washington
Michael H Court - Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, Pharmacogenomics Laboratory, Washington State University College of Veterinary Medicine, Pullman, Washington
Publication Details: Journal of veterinary pharmacology and therapeutics, Vol.41(6), pp.815-824
Academic Unit: Veterinary Clinical Sciences, Department of
Publisher: England
Grant note: D16CA-401 / Morris Animal Foundation R01 GM102130 / NIGMS NIH HHS GM102130 / US National Institutes of Health
Identifiers: 99900547435701842
Language: English
Resource Type: Journal article