Figure 18.

Cytochrome 450 enzymes (CYP) activities in hepatocytes derived from hPSCs (AS034, SA121, SA181, P11012, P11025, and ChiPSC6b) (N = 2) and cryopreserved human primary hepatocytes plated for 20 hr (hphep 20 h) (N = 4). CYP activities in hepatocyte cultures were measured after 29 days of differentiation by the following assay: the cells were incubated with CYP enzymes substrates phenacetin (CYP1A), midazolam (CYP3A), diclofenac (CYP2C9), bufuralol (CYP2D6), and mephenytoin (CYP2C19). The concentrations of the resulting metabolites paracetamol, 3-OH-midazolam, 4-OH-diclofenac, 1-OH-bufuralol, and 4-OH-mephenytoin were determined by liquid chromatography/mass spectrometry. The results were normalized to mg protein per well and the duration of CYP activity assay. The CYP activity is presented as pmol metabolite per mg protein per minute (mean ± SEM). The y-axis in log scale. (a) CYP1A, (b) CYP3A, (c) CYP2C9, (d) CYP2D6, and (e) CYP2C19.