Cellular ATP content of heated Chinese hamster ovary cells.

Hyperthermia at either 41.5 or 45 degrees C with variable heating times to reduce cell survival up to three orders of magnitude did not decrease significantly cellular ATP content when measured either immediately or up to 7 hr after a heat treatment. Similarly, cellular ATP content was not significantly reduced with step-down heating, precooling prior to hyperthermia, or thermotolerance induction. The data suggest that heat-induced depletion of intracellular ATP content is not a critical factor in the thermal death of cells heated under normal culture conditions.