INHIBITORY EFFECT OF ASCORBATE ON CELL-GROWTH - RELATION TO CATALASE ACTIVITY

The effect of ascorbate on cell growth was examined using primary cult ured hepatocytes and chondrocytes elicited from guinea pigs and six ki nds of cell lines derived from the tissue and blood of mammals. Cells were cultured in medium supplemented with or without ascorbate at vari ous concentrations for 24 and 48 h. There were differences among the c ells used here in the effect of ascorbate on growth, and also in the c oncentrations of ascorbate required to lower cell viabilities. This in dicates that different cell species have varying sensitivities to asco rbate in medium. On the other hand, cells such as HL-60, which showed growth inhibition at higher concentrations of ascorbate in medium amon g observed cells, were damaged by the exposure to higher concentration s of hydrogen peroxide (H2O2). Furthermore, there was a positive corre lation between the activity of catalase in cells that decomposed H2O2 and the concentration of ascorbate required to lower cell viability (p <0.01). These results indicate that the concentration of ascorbate in medium required to inhibit cell growth depends on the activity of cata lase in the cells.