Ethoxyresorufin

AαC was purchased from the Toronto Research Chemicals (Toronto, ON, Canada). [4b,5,6,7,8,8a-¹³C₆]AαC was a gift from Dr. Daniel Doerge, National Center for Toxicological Research (Jefferson, AR). Human liver microsomes were obtained from the Tennessee Donor Services, Nashville, TN, and kindly provided by Prof. F. P. Guengerich, Vanderbilt University. DMSO, ethoxyresorufin, methoxyresorufin, methanol, acetonitrile, ascorbic acid, hydrochloric acid, ammonium acetate, sulfatase from Helix pomatia (≥10,000 units/g solid) and β-Glucuronidase from Helix pomatia (≥30,000 units/g solid) were purchased from Sigma Aldrich (St. Louis, MO, USA). AαC-3-OH and AαC-6-OH were prepared with human liver microsomes or rat liver microsomes and spectroscopically characterized as previously reported.^{17 (link),34 (link)}N-(deoxyguanosin-8-yl)-2-amino-9H-pyrido[2,3-b]indole (dG-C8-AαC) and [¹³C₁₀]-dG-C8-AαC were prepared as previously described.^{27 (link)}

NNK, [¹³C₆]NNK, [CD₃]-O⁶-mG, and [4-CD₂,CD3]NNAL-O-Gluc were purchased from Toronto Research Chemicals (Toronto, ON). NNAL and [¹³C₆]NNAL were synthesized from NNK or [¹³C₆]NNK via sodium borohydride reduction.^{10 (link)} (±)-DHM and (±)-DHK were synthesized in house with a slight modification of a reported procedure.²⁵ AIN-G powdered diet was purchased from Harlan Teklad (Madison, WI). Recombinant β-glucuronidase was purchased from Sigma-Aldrich (St. Louis, MO). Ethoxyresorufin was purchased from Sigma-Aldrich. NADPH was purchased from RPI (Mount Prospect, IL). The qPCR primers were purchased from IDT (Coralville, IA), and the sequences are as follows: Gapdh, 5′-AACTTTGGCATTGTGGAAGG-3′ (sense) and 5′-ACA-CATTGGGGGTAGGAACA-3′ (antisense); Ahr, 5′-AGCCGGTGC-AGAAAACAGTAA-3′ (sense) and 5′-AGGCGGTCTAACTCTGT-GTTC-3′ (antisense); Cyplal, 5′-GGTTAACCATGACCGGGA-ACT-3′ (sense) and 5′-TGCCCAAACCAAAGAGAGTGA-3′ (antisense); Cyp1a2, 5′-TGGAGCTGGCTTTGACACAG-3′ (sense) and 5′-CGTTAGGCCATGTCACAAGTAGC-3′ (antisense). All other chemicals or solvents were purchased from either Fisher Scientific (Fairlawn, NJ) or Sigma-Aldrich, unless stated otherwise.