13c6 nnk

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.

The AIN-93G and AIN-93M powdered mouse diets were purchased from Harlan Teklad (Cambridgeshire, UK). Natural DHM was isolated from a kava product supplied by Gaia Herbs, Inc. (Brevard, NC), following reported protocols.^{20 (link)} NNK, [¹³C₆]NNK, [¹³C₆]NNAL, [CD₃]O⁶-mG and [4-CD₂, CD₃]NNAL-O-gluc were purchased from Toronto Research Chemicals (Toronto, ON, Canada).^{22 (link)}O⁶-methylguanine (O⁶-mG) was purchased from Midwest Research Institute (Kansas City, MO). 7-[4-(3-Pyridyl)-4-oxobut-1-yl]guanine (7-pobG), O²-[4-(3-pyridyl)-4-oxobut-1yl]thymidine (O²-pobdT), O⁶-[4-(3-pyridyl)-4-oxobut-1-yl]-2′-deoxyguanosine (O⁶-pobdG), 7-[4-(3-pyridyl)-4-hydroxobut-1-yl]guanine (7-phbG), O²-[4–(3-pyridyl)-4-hydroxobut-1yl]thymidine (O²-phbdT), O⁶-[4-(3-pyridyl)-4-hydroxobut-1-yl]-2′-deoxyguanosine (O⁶-phbdG) and their corresponding deuterated analogs were synthetized following reported procedures.^{23 (link),24 (link)} Micrococcal nuclease and phosphodiesterase II were purchased from Worthington Biochemical Corporation (Lakewood Township, NJ). Alkaline phosphatase was from Roche Molecular Biochemicals (Pleasanton, CA).