Bicarbonate as an essential for human cells in vitro

Human conjunctival and Hela cells were grown in vitro in the presence or absence of HCO 3 −. In the presence of HCO 3 −, multiplication of both cell strains was rapid; whereas, in its absence, a decrease in the number of cells was found. Such a decrease was small if the medium was changed on alternate days, presumably because of transient exposure of the cells to CO 2. At any time studied up to 14 days, cell multiplication was restored by the addition of HCO 3 − to the medium.