Several stresses are known to induce synthesis of heat shock protein. The present study was performed to see whether pulmonary ischemia, induced by the bronchial artery occlusion, produced HSP70 in cat lung. To this aim we compared experimental and control groups of cats with respect to the HSP70 production in the lung. Experimental animals were subjected to 10-min bronchial artery occlusion followed by reperfusion. The interval between the end of the occlusion and the end of the reperfusion was 1 hour, 4 hours and 8 hours, whereas control animal was not subjected to any manipulation except anesthesia. According to the interval differences, experimental animals were divided into 1HR, 4HRs and 8HRs groups. To determine the induction of HSP70 in each group, total proteins of lung tissues were extracted and separated by PAGE electrophoresis. Immunoblotting with a mouse monoclonal anti-HSP70 IgG antibody revealed that HSP70 was not detected in the pulmonary tissues resected from control, 1HR or 4HRs groups. In contrast, HSP70 expression in 8HRs group was marked. These results suggest that pulmonary ischemia by the bronchial artery occlusion produces HSP70 in a delayed