LOCALIZATION OF CYTOCHROME-P-450 GENE-EXPRESSION IN NORMAL AND DISEASED HUMAN LIVER BY INSITU HYBRIDIZATION OF WAX-EMBEDDED ARCHIVAL MATERIAL

The localization of the expression of several cytochrome P-450 genes in normal and diseased human liver was investigated by in situ hybridization of formalin-fixed, paraffin wax-embedded archival tissue samples with S-35-labeled antisense RNA probes. The results demonstrated that genes coding for members of the cytochrome P-450 3A subfamily (CYP3A) were preferentially expressed in hepatocytes in acinar zone 3 (the centrilobular region), whereas genes coding for CYP1A2, CYP2A, 2B and 2C were expressed uniformly throughout the liver acinus. In cirrhotic livers, CYP2A and 2B genes (and to a lesser extent, CYP3A genes) were highly expressed in isolated hepatocytes located at the junction of parenchyma with fibrous septa. The cause and significance of the position-dependent expression of specific cytochrome P-450 genes in normal and diseased human liver are discussed.