Intravenous lysine vasopressin lowers body temperature in normal and febrile pigs

Vasopressin has been implicated as a centrally acting endogenous antipyreti c. However, in several species, including the pig, plasma vasopressin conce ntrations increase during the early stages:of fever. This experiment invest igated the effects of intravenous lysine vasopressin on core temperature in normal and febrile swine. Lysine vasopressin (20 mu g/pig) stimulated cort isol release and induced a 60-min hypothermic episode in normal animals, al though a 10-fold lower dose was without effect. The peptide also delayed th e pyretic response to bacterial endotoxin (20 mu g intravenously). It is sp eculated that the hypothermic action of circulating vasopressin may involve nitric oxide. (C) 1999 Elsevier Science Inc. All rights reserved.