Although research on regenerative medicine using iPS cells has markedly progressed, no culture medium meeting the objective of studies on cell differentiation using iPS cells has been developed. The establishment of the in vitro cell growth method and development of MEM and DMEM as cell culture media have facilitated the stable growth of many types of cultured cell. These culture media are of marked historical value in cell culture methods, and they are used for the cell differentiation of iPS and ES cells without modification as the standard media. There are only a few reports providing a basis for the essential amino acid contents of these culture media.To develop a new culture medium for cell differentiation, we started a basic investigation of the essential amino acid contents using mouse-derived ES-D3 cells which do not require feeder cells. Dulbecco's Modified Eagle Medium (DMEM) is normally used for ES-D3 cell culture. The essential amino acid content of DMEM is higher than that of Minimum Essential Medium (MEM). Of the 7 essential amino acid contained in MEM, the contents of 6 amino acids are lower than those of DMEM excluding L-arginine. Thus, we investigated the influence of the 6 essential amino acids excluding L-arginine by adding them individually to MEM, and the viability and differentiation rate of ES-D3 cells were investigated. The addition of L-glutamine improved the cell viability and differentiation rate. It was clarified that the accumulation of data on the differentiation of various cells is necessary to determine the appropriate essential amino acid contents, aiming at the preparation of culture media for regenerative medicine.
