title: Intra-individual variation and sex differences in gene expression of cytochromes P450 in circulating leukocytes.
abstract: To clarify partly inconsistent results in gene expression of cytochromes P450 (CYP) in the circulation, we undertook a systematic study over a long time period in 19 healthy men and women. CYP specific mRNA for 1A2, 1B1, 2E1 and 3A4 was studied in the leukocytes collected repeatedly on 20 occasions over a 10-week period. Our study revealed a varying pattern of CYP expression over time. CYP3A4 specific mRNA exhibited the largest intra-individual variation with an average coefficient of variation between 40 and 250%. CYP1B1 and CYP2E1 did not vary as much (39-110%). CYP1A2 was sporadically detected in only ten individuals, but varied considerably when measurable (61-256%). The expression in CYP1B1 was significantly higher in women than in men (P = 0.02). We conclude that CYP gene expression in blood varies considerably over time. It is conceivable that the variation reflects a hitherto unknown influence of exogenous or endogenous factors such as hormones, cytokines, and other circulating factors on the hematogeneous cytochromes.
authors.affiliation: Department of Medical Laboratory Sciences and Technology, Karolinska Institutet at Huddinge University Hospital, Stockholm, Sweden. nfinnstrom@sangtec.se
authors.forename: N
authors.initials: N
authors.lastname: Finnström
authors.forename: B
authors.initials: B
authors.lastname: Ask
authors.forename: M-L
authors.initials: ML
authors.lastname: Dahl
authors.forename: M
authors.initials: M
authors.lastname: Gadd
authors.forename: A
authors.initials: A
authors.lastname: Rane
mesh_terms: D000328:Adult; D019540:Area Under Curve; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000097:blood / Q000235:genetics*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D014644:Genetic Variation / Q000502:physiology*; D006801:Humans; D007962:Leukocytes / Q000201:enzymology*; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D012727:Sex Characteristics; D018709:Statistics, Nonparametric
chemical_list: D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System