Growth-and density-dependent inhibition of deoxyglucose transport in Balb 3T3 cells and its absence in cells transformed by murine sarcoma virus.

The earliest measurable parameter that shows density-dependent inhibition is the uptake of [(3)H]deoxyglucose by Balb 3T3 cells. The rate decreases even during the exponential phase of growth and reaches a minimum, about 8- to 10-times lower than maximum, as the culture approaches the saturation density. Cells transformed by murine sarcoma virus fail to show either growth-dependent or density-dependent inhibition of deoxyglucose uptake. Treatment with dibutyryl cyclic AMP in the presence of theophylline results in premature cessation of growth and in an arrest in the decline of deoxyglucose transport. Culture in serum-deficient medium also produces rapid inhibition of growth at low cell density, but these cultures exhibit a markedly decreased rate of deoxyglucose uptake.