Hormone responsive expression. Microarray expression data were retrieved from the 'Genevestigator' database and processed as described in Material and Methods. Background corrected expression intensities were compared to untreated control experiments and log2-ratios were used. Genes that are up- or down-regulated (>twofold) in more than 30% of each treatment group as indicated were selected. a) Number of P450s which are responsive to each treatment. b) Hierarchical cluster analysis with complete linkage. The resulting heatmap is color coded as indicated.