biostudies-literatureLiu JNIH ResearchNCRR NIH HHSNIDDK NIH HHSNIEHS NIH HHSNIH TrainingIntramural EPA279-286https://www.ebi.ac.uk/biostudies/studies/S-EPMC8215780biostudies-literatureUnknown51(3)Individual differences in cytochrome P450 (CYP) enzymes contribute to responses to drugs and environmental chemicals. The expression of CYPs is influenced by sex, age, and ethnicity. Human CYP studies are often conducted with human liver microsomes and liver cells to evaluate chemical induction and drug interactions. However, the basal or constitutive expression of CYP transcripts and enzyme activities in the intact liver are also important in our understanding of individual variation in CYPs. This study utilised 100 human liver samples to profile the constitutive expression of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4, and 4A11 enzyme activity and transcript levels. The mRNA expression of the CYPs and xenobiotic receptors <i>AhR</i>, <i>CAR</i>, and <i>PXR</i> was examined <i>via</i> qPCXenobiotica; the fate of foreign compounds in biological systemsExpression of cytochrome P450 isozyme transcripts and activities in human livers.PMC8215780R01 DK081461T32 ES007079ES-09716R01 ES013714EPA999999ES-009649ES-07079RR-021940ES-013714P20 RR021940R01 ES009716DK-081461R01 ES009649Lu YFKlaassen CDLiu JCorton JCfalseExpression of cytochrome P450 isozyme transcripts and activities in human livers.Individual differences in cytochrome P450 (CYP) enzymes contribute to responses to drugs and environmental chemicals. The expression of CYPs is influenced by sex, age, and ethnicity. Human CYP studies are often conducted with human liver microsomes and liver cells to evaluate chemical induction and drug interactions. However, the basal or constitutive expression of CYP transcripts and enzyme activities in the intact liver are also important in our understanding of individual variation in CYPs. This study utilised 100 human liver samples to profile the constitutive expression of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4, and 4A11 enzyme activity and transcript levels. The mRNA expression of the CYPs and xenobiotic receptors <i>AhR</i>, <i>CAR</i>, and <i>PXR</i> was examined <i>via</i> qPC2021-01-01T00:00:00Z2021 Mar2025-04-04T10:16:02.294Z2025-04-04T10:16:02.294ZS-EPMC82157803335034210.1080/00498254.2020.1867929