ABSTRACT:Cryopreserved rat hepatocytes entrapped within an alginate matrix, commercially available as Liverbeads, were evaluated for their relevance as a screening tool for gene induction in vitro, using quantitative real-time reverse transcriptase-polymerase chain reaction. They were treated with the reference compounds ␤-naphthoflavone (BNF), phenobarbital (PB), pregnenolone 16␣-carbonitrile (PCN), and clofibric acid (CLO) and analyzed for mRNA levels of Cyp1a1, Cyp2b1, Cyp3a1, Cyp4a1, Ugt1a6, and Ugt2b1. In addition, for PB and PCN, the results were compared with those obtained in rat liver in vivo. For each inducer, the gene induction profiles obtained with the Liverbeads in vitro model were time-and dose-dependent. The in vitro gene expression profiles confirmed the corresponding known P450 and UGT induction by each reference compound.