Time-dependent increase in the resistance of mammalian cell protein synthesis to inhibition by hypertonic medium

As a result of continued incubation of cultured L-929 fibroblasts in growth medium containing excess NaCl, protein synthesis became resistant to the inhibitory effect of hypertonic medium. Protein synthesis became progressively resistant in a linear fashion during the first 6 h of incubation. The level of resistance attained was directly related to the concentration of excess NaCl to which the cells were exposed during the incubation period. Actinomycin D did not prevent the expression of resistance, indicating that de novo synthesis of RNA is not required. Finally, resistance declined to near the preinduction level by 4 h after resistance cells were returned to isotonic medium.