Abstract

The pyrogenic action of a highly purified preparation of enterotoxin from staphylococcal strain S6 was investigated in unanesthetized and unrestrained cats chronically prepared with indwelling venous catheter, cerebroventricular cannula and retroperitoneal thermocouple. Maximum peak fever was obtained with 0.02 µg (total) of enterotoxin administered intraventricularly as contrasted with 1.0 µg/kg required intravenously. The pyrogenic response to intravenous injection of enterotoxin was characterized by a biphasic fever pattern, whereas intraventricular injection elicited only a monophasic response. Tolerance to the pyrogenic effect developed after repeated injection of enterotoxin regardless of the route of administration, and cross-tolerance was manifested between routes of injection. On the other hand, no remarkable pyrogenic cross-tolerance could be demonstrated between staphylococcal enterotoxin and endotoxin from S. typhosa when these agents were tested through various combinations of intravenous and intraventricular administration.