Nucleoside restoration of heat resistance and suppression of glucose-regulated protein synthesis by glucose-deprived L929 cells.

Depriving cultured cells of glucose increases glucose-regulated protein synthesis, suppresses heat shock protein synthesis, and increases sensitivity to killing by hyperthermia. The present study shows that supplementation of glucose-free culture medium with uridine or a number of other nucleosides reverses all these effects of glucose deprivation. Uridine is more effective in this regard than equimolar concentrations of glucose, and ribose is relatively ineffective. Uridine does not suppress glucose-regulated protein synthesis that has been induced by glycosylation inhibitors, calcium chelation, or anoxia. We infer from these data that the effects of glucose deprivation may result from inhibition of ribonucleoside synthesis and that ribonucleosides may be directly involved in regulating glucose-regulated protein and heat shock protein synthesis as well as in protecting cells against hyperthermic cytotoxicity.