Change in fibrinogen turnover in tumors by hyperthermia

The effect of hyperthermia on the turnover of fibrinogen and albumin in the SCK tumor of A/J mice was studied. Immediately after heating at 43.5 degrees C for 30 min, the content of 131I-labeled fibrinogen in the tumors was about 2.7-fold that in the control tumor and remained elevated for 24 hr. On the other hand, the content of 125I-labeled serum albumin in the tumor immediately after heating was only 1.7-fold that in the control tumor and started to decrease soon after heating. The greater increase in the accumulation and the longer retention of the labeled fibrinogen as compared with the labeled albumin in the heated tumors appeared to be related to the heat-induced vascular damage accompanied by vascular occlusion, fibrination and subsequent thrombus formation.