Uptake and oxidation of malonaldehyde by cultured mammalian cells

Primary cultures of rat skin fibroblasts were used as a model system to investigate the cellular uptake and oxidation of malonaldehyde (MA). The cells were grown in a medium containing 10(-5) M, 10(-4) M or 10(-3) M concentrations of [1,3-14C]MA. There was a limited, concentration-dependent uptake of MA by 24 hr (approximately 4% at all concentrations). The uptake of [1,2-14C]acetate by 24 hr was in the major lipids. Despite its low uptake and rapid oxidation to CO2, pretreatment of the cells with 10(-3) M MA for 24 hr produced a latent inhibition of [14C]glucose oxidation. Limited cellular uptake of MA may explain the tolerance of cells grown in culture to relatively high MA concentrations.