Uptake of glycerol by tumor cells and its control by glucose.

Glycerol can be utilized by cultured cells of Novikoff rat hepatoma, Hela and HEP-2. Glucose inhibits the rate of glycerol uptake by the first two cell lines but stimulates the process in the third. The transport process of glycerol, particularly by its insensitivity to phloridzin, is distinguishable from that of glucose. The inhibitory effect of glucose on glycerol uptake which is competitive in nature is at the membrane transport and not phosphorylation step, since $\text{in vitro}$ glycerol kinase is sensitive to neither glucose nor hexose phosphates.