Hierarchical cluster analysis of differentially expressed transporters genes in primary rat hepatocytes cultures. Data were represented as expression values relative to the freshly isolated hepatocytes (day 0) at p < 0.05. Each column represents a selected culture time point (day 1, 2, 3, and 4) and whole liver (column 1), shades of red and green indicate up- or down-regulation of genes according to the color scheme shown. Black indicates no change. Genes represented by rows were clustered according to their similarities in pattern of expression. Slc, solute carrier organic transporter; ABC, ATP-binding cassette; DDCt, ΔΔCt.