Rb+ influxes differentiate between growth arrest of cells by different agents.
The effect of cell cycle on Rb+ (K+) fluxes was studied in NIH 3T3 mouse fibroblasts. Serum starvation or isoleucine deprivation resulted in cell arrest at an early G1/G0 phase, accompanied by a marked decrease in both ouabain-sensitive and ouabain-resistant Rb+ influx. On the other hand, cells arrested at late G1/G0 phase by hydroxyurea treatment have high ouabain-sensitive and ouabain-resistant Rb+ influx. Butyric acid treatment resulted in cell arrest at an early G1/G0 phase, but in contrast to serum or isoleucine starvation did not decrease Rb+ influxes. It is thus shown that quiescent cells may have Rb+ influx rates as high as that of logarithmically growing cells. The results are consistent with the hypothesis that an increased ion permeability of the cell is initiated at a critical stage in G1/G0 phase, and that butyric acid may arrest the cell beyond that stage.
D000818:Animals; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002453:Cell Cycle / Q000187:drug effects; D007399:Interphase; D007473:Ion Channels / Q000378:metabolism; D007532:Isoleucine / Q000494:pharmacology; D051379:Mice; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D012413:Rubidium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism
D002087:Butyrates; D007473:Ion Channels; D007532:Isoleucine; D020148:Butyric Acid; D010042:Ouabain; D012964:Sodium; D012413:Rubidium; D011188:Potassium