Transient heat shock in mid-G1-phase of the C6 glioma cell cycle impairs entry into S-phase.

Synchronous populations of rat C6 glioma cells have been obtained by a mitotic selection procedure and used to establish the effect of transient temperature elevation on their progression through the cell cycle. A transient 3-h exposure to a 42 degree C heat shock within defined area in the mid-G1-phase of the cell cycle has been demonstrated to impair progression to S-phase. This anti-proliferative heat shock effect was not apparent in asynchronous cell populations. A small, but significant, decrease in 3H-thymidine incorporation was observed (approximately 5%) following an 8-h exposure to heat shock.