Density‐dependent resistance to puromycin in cell cultures

Pig kidney cells exhibit resistance to puromycin when cultured at high cell densities, growing progressively in otherwise lethal concentrations of drug. Comparison of population growth of cultures inoculated at different densities indicates that survival in puromycin is a function of cell density. Uptake of puromycin from culture media is less at higher cell densities resulting in decreased inhibition of protein synthesis by puromycin. Enhanced survival in puromycin at high population densities is attributed to reduced accumulation of puromycin from the culture media.