Hyperthermia, unlike ionizing radiation and chemical oxidative stress, does not stimulate proteolysis in erythrocytes

1. 1. Oxidative stress by phenazine methosulfate stimulated proteolysis in erythrocytes. 2. 2. Gamma-irradiation of erythrocytes in the range of 50-1000 Gy also resulted in the induction of proteolysis. 3. 3. Though it has been suggested that hyperthermia imposes an oxidative stress on a cell, hyperthermic exposure of erythrocytes (30 min, 39-49°C) did not stimulate proteolysis during subsequent incubation of whole cells or hemolysates. 4. 4. Proteolytic degradation of spectrin was accelerated during incubation of membranes isolated from cells heated above 45°C but this effect seems to be due rather to thermal denaturation of spectrin than to oxidative modification of cellular proteins by hyperthermia.