Nucleotide metabolism in the heart subjected to heat stress.

Abstract

Heat shock increases cardiac resistance to ischemia but the mechanism of this effect is unknown.1 Whole body hyperthermia has been recognised to induce synthesis of a group of proteins, termed “heat shock proteins” (HSP). The predominant function of HSP is protection against protein denaturation and facilitation of desired protein folding at the time of ribosomal polypepide synthesis. Furthermore HSP are able to unfold the polipeptide chains, by associating with proteins being incorporated into mitochondria and placing them in a translocation-competent configuration. These roles are referred to as “chaperone” functions.2 There is strong evidence to suggest that increased expression of heat shock protein HSP70 is directly involved in the cardioprotective effect of heat stress.3,4 However it is not yet known which enzymes or structural proteins and which metabolic pathways are protected by HSP70. To investigate the possible role of alterations in nucleotide metabolism in this beneficial effect, we analysed the concentrations of adenine, guanine, pyrimidine and pyridine nucleotides and phosphocreatine concentration in the rat heart subjected to heat shock. The concentrations of nucleotide metabolites were evaluated under normoxic conditions and after 5 min of global normothermic ischemiaKeywordsHeat StressHeat Shock ProteinPyridine NucleotideNucleotide MetabolismHeat Shock Protein HSP70These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.