Glucocorticoids increase the length of the G2 and M phases of the HeLa S3 cell cycle.
Glucocorticoids increase the size and content of RNA and protein in randomly growing HeLa S3 cells; however, the rates of growth and macromolecule synthesis are not effected. In synchronized populations of HeLa S3 cells, addition of 10(-7) M dexamethasone at the G1/S border causes a 1 h delay in cell division. The length of the S phase, determined in synchronized cells by incorporation of [3H] thymidine into acid precipitable material, is unaffected by glucocorticoids. Thus, the 1 h prolongation occurs during the G2/M phases, when the cells are largest, and accounts for the increase in the size and content of RNA and protein. As with the induction of specific proteins, the events producing the G2 effects are initiated during the S phase of the cell cycle. Thus, the HeLa S3 cells contain a G2 regulatory point, which is influenced by glucocorticoids.
Fanger
B O
BO
Department of Physiology, University of North Carolina, Chapel Hill 27514.
Schreifer
J
J
Cidlowski
J A
JA
D002453:Cell Cycle / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D006367:HeLa Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007399:Interphase / Q000187:drug effects*; D007700:Kinetics; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
D014316:Tritium; D003907:Dexamethasone; D013936:Thymidine