HEAT-SHOCK ACTIVATION OF NFKB IN RAT-LIVER IS MEDIATED BY INTERLEUKIN-1

Exposure to high temperature (heat shock) activates the transcription factor NFkB in the liver of the living rat, but is not effective in he patoblastoma cells in culture: on the contrary, activation of the heat shock transcription factor (HSF) occurs under both conditions. Pre-tr eatment of the rat with IL-1 receptor antagonist suppresses the activa tion of NFkB, which seems to be mediated by the release of this cytoki ne, but does not hamper the activation of HSF and the concurrent induc tion of hsp 70 mRNA. IL-1 activity actually shows a strong, albeit tra nsient, increase in the blood of heat shocked rats.