title: Increase of epidermal growth factor-stimulated cell-cycle progression and induction of thermotolerance by heat shock: temperature and time relationship.
abstract: When quiescent confluent cultures were incubated at increased temperature and then incubated at 37 degrees C prior to a second increase of temperature (46 degrees C) it appeared that heat-induced morphological alteration and ability to proliferate could be influenced by the previous thermal history of the cells. Incubations for 20 min in a temperature range of 41-46 degrees C caused cells to develop thermo-tolerance within 3 h of incubation at 37 degrees C. Confluent quiescent Swiss mouse 3T3 cells were incubated at 41.8, 43.7 or 45.6 degrees C and then reincubated at 37 degrees C to determine the effects of heat shock on the mitogenic effects of epidermal growth factor (EGF). Preincubation at 43.7 degrees C or 45.6 degrees C enhanced stimulation of G1-S progression by EGF. Preincubation at 43.7 degrees C markedly increased the rate at which cells enter the S phase without changing the length of the lag phase. A comparison of the duration of incubation at 43.7 degrees C for potentiation of EGF-induced DNA synthesis and that for induction of thermotolerance showed that a similar time interval for induction of effect could be implied.
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects*; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis / Q000528:radiation effects; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006358:Hot Temperature / Q000009:adverse effects*; D007399:Interphase / Q000187:drug effects / Q000528:radiation effects; D051379:Mice; D013696:Temperature; D013997:Time Factors
chemical_list: D004815:Epidermal Growth Factor; D004247:DNA