INTERINDIVIDUAL DIFFERENCE IN EXPRESSION OF HUMAN AH RECEPTOR AND RELATED P450 GENES

The genomic clones of human aryl hydrocarbon receptor (Ahr) and Ahr nu clear translocator (Arnt) were isolated, and the structures of exon-in tron junctions of these genes were partially determined. Based on the sequence information, a quantitative RT-PCR analysis was developed, an d the expression of these genes was studied in various human tissues. mRNAs for Ahr and Arnt were widely expressed in human tissues and abun dantly in lung. Individual difference in expression levels of Ahr and Arnt mRNA was observed in liver, lung and blood. In order to examine w hether expression levels of Ahr and Arnt were associated with those of CYP1A1, we studied the expression of these mRNAs in blood among 20 he althy subjects, taking account of individuals' cigarette smoking habit s. We found that the expression levels of CYP1A1 appeared to associate with those of Ahr and Arnt mRNAs (P < 0.06), and also that the expres sion of Ahr and Arnt was influenced by cigarette smoking. The expressi on of human Ahr and Arnt is reported here for the first time, providin g a quantitative RT-PCR analysis as a useful tool for further studies.