Antagonistic effects of insulin and dexamethasone on glucose-regulated and heat shock protein synthesis.

The present study extends our previous observation (Kasambalides and Lanks, J. Cell. Physiol., 114:93-98, 1983), that dexamethasone inhibits the alterations in heat shock protein (HSP) and glucose-regulated protein (GRP) synthesis caused by glucose deprivation. We now show that insulin, even in the presence of high extracellular glucose concentrations, will induce 95K and 82K GRP synthesis while suppressing 85K and 69K HSP synthesis. Heat shock of insulin-treated cultures causes induction of the 82K GRP rather than the 85K and 69K HSP's. All of the insulin effects are antagonized by dexamethasone. These data suggest that the changes in GRP and HSP synthesis induced by glucose deprivation and heat shock, respectively, may reflect the operation of a normal physiological mechanism that regulates glucose metabolism.