Potent inhibition of cytochrome P450 2B6 by sibutramine in human liver microsomes

Selective Inhibition of Cytochrome P450 2D6 by Sarpogrelate and Its Active Metabolite, M-1, in Human Liver Microsomes

“…So-called cocktail assays in which several enzyme activities are determined in parallel by liquid chromatographytandem mass spectrometry (LC-MS/MS) are particularly useful. The inhibitory potencies of sarpogrelate and M-1 were determined as described previously with slight modification (Bae et al, 2013). Phenacetin O-deethylase, coumarin 7-hydroxylase, bupropion 6-hydroxylase, rosiglitazone p-hydroxylase, tolbutamide 4-hydroxylase, S-mephenytoin 4-hydroxylase, dextromethorphan O-demethylase, chlorzoxazone 6-hydroxylase, and midazolam 19-hydroxylase activities were determined as probe activities in human liver microsomes for CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4/5, respectively.…”

“…Sarpogrelate or M-1 (concentration: 0-50 mM) and all substrates were dissolved in acetonitrile and serially diluted with acetonitrile to the required concentrations to give a final organic solvent concentration of 1.0% in the incubation mixture. Concentrations of P450-selective substrates were used close to their reported K m values (Supplemental Table 1; Kim et al, 2005;Bae et al, 2013).…”

“…Equilibrium dialysis was conducted to assess the unbound fraction of sarpogrelate or M-1 in human liver microsomes and human plasma using a single-use plate rapid equilibrium dialysis device with dialysis membranes with a molecular weight cutoff of ;8000 Da (Thermo Scientific, Rockford, IL) (Bae et al, 2013). Human liver microsome samples containing sarpogrelate or M-1 at concentrations of 0.5 and 10 mM, respectively (100 ml), were dialyzed against 50 mM phosphate buffer (300 ml) at pH 7.4.…”

“…Metabolites of nine P450-selective substrates were analyzed using a tandem quadrupole mass spectrometer (QTrap 5500 LC-MS/ MS; Applied Biosystems, Foster City, CA) equipped with an electrospray dmd.aspetjournals.org ionization interface, as reported previously (Bae et al, 2013). Single reaction monitoring mode using specific precursor/product ion transition was used for quantification.…”

Effect of tetrahydrocurcumin on the profiles of drug-metabolizing enzymes induced by a high fat and high fructose diet in mice

“…Cyp2b is involved in the metabolism of anticancer drugs such as cyclophosphamide, ifosfamide, and tamoxifen, and other clinical drugs such as efavirenz and propofol [48] and plays a role in the metabolism of endogenous substance such as testosterone. Cyp2b is also regulated by many endogenous hormones, e.g., glucocorticoids, sex hormones, and growth hormone in association with many nuclear receptors including the constitutive androstane receptor (CAR), the pregnane X receptor (PXR), and the glucocorticoid receptor (GR) [49,50].…”