OBJECTIVETo elucidate gene expressions of phase II enzymes in the mouse embryonic stem (ES) cell-derived hepatocytes.

METHODSEmbryoid body (EB) formation cultures were applied in directed differentiation of ES to hepatic-like cells. The expressions of hepatic-specific genes, including AFP, ALB, Cyp7a1, were detected by RT-PCR during the differentiation course. Albumin was detected by immunocyto- chemistry. The gene expressions of mGST1 and UGTs family, including UGT1a1, UGT1a6, UGT1a9 and UGT2b5, were investigated using RT-PCR.

RESULTSA notable gene expression of AFP and ALB was observed on d 8. On d 18, AFP gene failed to express, while ALB and Cyp7a1 genes were detected.Albumin-positive staining was detected in hepatic-like cells. Phase II enzyme genes expressed in variance during the differentiation course, UGT1a1 and UGT1a9 were expressed stably, UGT1a6 expression increased gradually, and UGT2b5 failed to express. Little mGST1 gene expression could been detected in the early course until d 18. In addition, all the enzymes gene expressions in the derived hepatocytes on d 18 were similar to those from mature mouse hepatocytes.

CONCLUSIONSMouse ES cell-derived mature hepatocytes express phase II enzyme UGTs and mGST1 genes similar to those in mature hepatocytes. The system may offer an alternative animal testing model related to phase enzymes in further research.