found to be from greater than 0 to 0 6 an air filter mfd by gelman science 7 5 cm 2 was attached to the lid of a 200 ml tapping culture flask in such a manner that an oxygen containing gas stream was introduced therethrough into the container 80 ml of a dm160 au medium mfd by kyokuto seiyaku kogyo k k containing 10 of new born bovine serum was fed into the container and then inoculated with seed cells jtc 1 strain rat abdominal hepatoma cells at a concentration of 1 u00d7 10 6 cells ml then the cells were cultured under conditions of stirring at 400 rpm 37 u00b0 c and a co 2 incubator the culture medium was centrifuged at 1200 rpm for 10 minutes every two days and the centrifugally separated cells were placed in a new medium i e exchange the whole medium the initial glucose concentration of the culture medium was adjusted to 3500 ppm at the time of each exchange before and after each exchange of the whole medium 2 ml portions of the culture medium were sampled and the glucose concentration and lactic acid concentration of each sample was measured with an enzyme sensor further the cell concentration was measured with a hemacytometer fig1 shows the results the cells grew well and the cell concentration reached 1 u00d7 10 7 cells ml on the tenth day the l g was as high as 0 5 at the early part of the cultivation then slowly decreased and finally reached 0 3 thus it was found that an l g of 0 6 or below indicated that the cultivation conditions were aerobic and a sufficient amount of glucose was supplied.