摘要:The P19CL6 cell-line, a clone of the P19 mouse embryonal carcinoma cell-line, has been exten-sively used as a model for cardiomyocytes as these cells can be differentiated into a cardio-myocyte phenotype upon incubation with di-methyl sulfoxide. Uniquely, these cells can be observed to “beat” when monitored by mi-croscopy. We started investigating the response of P19CL6 cells to fatty acids, but highly vari-able results lead us to investigate the phenotype of the P19CL6 cells in more depth. In this study we demonstrated that the P19CL6 cells are re-sponsive to adrenaline, but loose the “beating” phenotype after 16 passages in culture. Analysis of specific mRNA transcripts indicated that the P19CL6 cells express both cardiac- and skeletal muscle-specific genes, while global analysis of microarray data showed clear differences be-tween the P19CL6 cells and cardiac tissue of embryonic or adult origin. In conclusion, our observations suggest caution in the use of the P19CL6 cells as a model of cardiomyocytes unless rigorous validation for the intended analysis has been undertaken.