title: Ethnic differences between Japanese and Caucasians in the expression levels of mRNAs for CYP3A4, CYP3A5 and CYP3A7: lack of co-regulation of the expression of CYP3A in Japanese livers.
abstract: Using a newly developed real-time reverse transcriptase-polymerase chain reaction method, mRNAs were quantitated for CYP3A4, CYP3A5 and CYP3A7 in adult livers from 24 Japanese and 24 Caucasian subjects to elucidate the potential ethnic differences in the expression levels of human cytochrome P450 (CYP) 3As. The expression level of CYP3A4 mRNA in Japanese livers (n = 24) was approximately three times higher than that in Caucasian livers (n = 24, p < 0.001). The mean level of CYP3A5 mRNA was approximately twice higher in Japanese (n = 9) than in Caucasians (n = 5) heterozygous for the CYP3A5 *1 allele (p = 0.057). The CYP3A7 mRNA level was twice higher in Japanese (n = 24) than in Caucasians (n = 22) carrying the CYP3A7 *1A/ *1A genotype (p = 0.042). The level of CYP3A4 mRNA did not correlate with those of CYP3A5 (r = 0.044, n = 24) or CYP3A7 (r = 0.21, n = 24) mRNAs in Japanese livers in contrast to co-regulatory expression of CYP3A4, CYP3A5 and CYP3A7 in Caucasian livers. The results indicate that there are ethnic differences in the expression levels of adult liver CYP3A mRNAs between Japanese and Caucasians, and that the mechanism(s) regulating the hepatic CYP3A expression may be different between these ethnic groups.
authors.affiliation: Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan. s-yamaori@hokuriku-u.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Yamaori
authors.forename: H
authors.initials: H
authors.lastname: Yamazaki
authors.forename: S
authors.initials: S
authors.lastname: Iwano
authors.forename: K
authors.initials: K
authors.lastname: Kiyotani
authors.forename: K
authors.initials: K
authors.lastname: Matsumura
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.forename: A
authors.initials: A
authors.lastname: Parkinson
authors.forename: K
authors.initials: K
authors.lastname: Nakagawa
authors.forename: T
authors.initials: T
authors.lastname: Kamataki
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics / Q000378:metabolism*; D044466:Asian People / Q000235:genetics; D003199:Computer Systems; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D008099:Liver / Q000201:enzymology*; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D044465:White People / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; C104464:CYP3A protein, human; C510164:CYP3A5 protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D010089:Oxidoreductases, N-Demethylating