Portal vein perfusion of the isolated rat liver: some markers of hyperthermic liver damage.

The cytotoxic effects of hyperthermia on tumours are readily measured. Parameters of injury to normal tissues are needed to evaluate therapeutic potential. Fifty-five isolated rat livers were perfused in vitro for 180 min in order to determine parameters of hyperthermic injury. During this period they were heated for 1 h at temperatures ranging from 37 degrees to 45 degrees and then assessed for evidence of hyperthermic injury. The most critical indicator of hyperthermic injury was sustained depression of bile production. Bile secretion decreased by 80% after heating at temperatures above 42 degrees. Aspartate amino transferase (AST) release increased significantly at temperatures of 42 degrees and above. Potassium and variable amounts of glucose were released into the medium during heating, reflecting temporary changes in metabolism at high temperatures.