Heat-induced thermotolerance expressed in the energy metabolism of mammalian cells.

Measurements were made of the effect of heat treatment on ATP levels in control and thermotolerant populations of murine lymphoma (L5178YS) and Ehrlich ascites cells to investigate whether the development of thermotolerance is associated with an increased ability of cells to maintain energy metabolism when challenged with heat treatment. For the L5178YS cells a single heat treatment produced a rapid reduction in ATP levels. However, previously heat treated L5178YS cells showed an increased ability to maintain ATP levels when challenged with a second heat treatment, and this ability to maintain ATP levels varied in a manner which correlated with the appearance and decay of thermotolerance seen in the parallel cell survival studies. In contrast both single and fractionated heat treatments did not reduce ATP levels in Ehrlich ascites cells.