DIBUTYRYL CYCLIC ADENOSINE 3' 5' MONOPHOSPHATE, SUGAR TRANSPORT, AND REGULATORY CONTROL OF CELL DIVISION IN NORMAL AND TRANSFORMED CELLS

Swiss 3T3 cells exhibit contact-regulated cell growth and have a lower ability to transport 2-deoxyglucose than polyoma (Py)-transformed 3T3 cells. Py3T3 cells treated with dibutyryl cyclic adenosine 3'5' monophosphate (dBcAMP) and theophylline have reduced cell growth and transport 2-deoxyglucose at the same rate as normal 3T3 cells. Evidence that the cessation of cell growth and reduced transport abilities in Py3T3 cells does not represent a return to contact-regulated growth comes from the following observations. First, treating high density Py3T3 cells with dBcAMP allows more than two doublings of cell number, even though ability to transport 2-deoxyglucose is returned to levels equal to those of normal 3T3 cells. Second, dBcAMP prevents serum-stimulated increases in 2-deoxyglucose transport in Py3T3 but not in 3T3 cells.