DEPRESSED EXPRESSION OF THE INDUCIBLE FORM OF HSP-70 (HSP-72) IN BRAIN AND HEART AFTER IN-VIVO HEAT-SHOCK

The heat shock gene expression plays a role in the protection of cells from injury. In the present study, we have analyzed the expression of heat shock protein (HSP) 72 (the major inducible form of the HSP 70 f amily) in different rat organs after a total body hyperthermia. The co ntent of HSP 72 was greatest in liver and colon. In contrast, accumula tion of HSP 72 was low in heart and brain (3-5% and < 1% of the amount in liver, respectively). This low expression of HSP 72 in heart and b rain could not be explained by a difference in the actual temperature within these organs. Analysis of cells in culture that resemble hepato cytes, myoblast, and neurons showed a pattern of HSP 72 expression sim ilar to that observed in liver, heart, and brain in vivo after heat sh ock. These results suggest that this disparate expression of HSP 72 is due to intrinsic characteristics of the cell types rather than to phy siological or environmental conditions. The differential expression of HSP 72 among different cell lines could be correlated with the differ ent levels of protein synthesis protection.