Impaired uptake of D-glucose by tumoral insulin-producing cells.

At variance with the situation found in normal pancreatic islets, no equilibration of extracellular and intracellular D-glucose concentrations occurs in tumoral insulin-producing cells of the RINm5F line. This unexpected behaviour may account, in part at least, for the abnormal kinetics of glucose utilization in the tumoral cells and their poor secretory response to this hexose.