Heat shock protein expression in response to stress and diabetes

The exposure of cells to a wide range of stressors results in a highly synchronized, genetically determined response, initiated by detection of the stressor, which in turn leads to a regulatory response that involves the elevated synthesis of a specific set of proteins, termed heat shock proteins (HSPs), which serve to counteract the initial damage,and re-establish cellular homeostasis. The expression of HSP30, 60, 70, and 90 was measured in the heart, liver, kidney, lung, and gonads of Japanese quail exposed to seven different stressors (mild restraint, loud noise, inescapable irritation, cold temperature, isolation in darkness and two stressful social situations), and in the heart, liver, kidney and lung of non-diabetic and diabetic rats exposed to seven individual stressors. Tonic Immobility (Tl) tests were also conducted on Japanese quail to assess whether or not the stressors increased fear response. Increased expression of HSP70 was found in the heart tissue of birds exposed to loud noise, inescapable irritation, cold temperature and isolation in darkness. The expression of other HSPs was not apparent in the heart or any of the other tissues examined. Longer Tl was observed only in birds exposed to the noise stress. Increased expression of HSP30 and HSP70 was found in the heart tissue of non-diabetic, stressed rats. Increased expression of HSP30 and HSP70 was also found in acute (4 weeks) and chronic (12 weeks) streptozotocin rats. In the liver, increased HSP70 expression was found for acute and chronic diabetic treatments. In the kidney, increased HSP70 expression was found only in chronic diabetes. No change in HSP 60 or 90 was detected in any tissues examined and the lung did not show any HSP increase. These results support the possibility of a tissue- and class-specific HSP response when exposed to a variety of stressors.Land and Food Systems, Faculty ofGraduat