Expression of heat shock protein 70 decreases with age in hepatocytes and splenocytes from female rats

A decline in the induction of heat shock protein 70 (hsp70) expression with age has been shown to occur in a variety of tissues from male rodents. Bec ause the age-related change in the expression of many genes often differ in male and female rodents, we have measured the induction of hsp70 expressio n in hepatocytes and splenocytes from young/adult (4-8 months) and old (20- 22 months) female Fischer 344 rats. Hepatocytes and splenocytes isolated fr om old female rats showed a marked decrease in the induction of hsp70 mRNA and protein levels by heat shock when compared to hepatocytes and splenocyt es isolated from young/adult female rats. Because the heat shock transcript ion factor HSF1 mediates the heat-induced transcription of hsp70, the effec t of age on HSFI was also studied. The ability of extracts from heat-shocke d splenocytes to bind to the heat shock element (HSE) decreased with age. I nterestingly, the levels of HSFI protein were similar in splenocytes and he patocytes from old female rats compared to young/adult female rats, even th ough the levels of HSE-binding were lower for splenocytes isolated from old rats. In this study, we show an age-related decline in the expression of h sp70, and this decline was similar to what we had previously observed in ma le Fischer 344 rats. (C) 1999 Elsevier Science Ireland Ltd. All rights rese rved.