Abstract: The role of arginine vesopressin (AVP) in the tolerance to endotoxin fever was observed in rabbits. The results showed① injection of AVP - antiserum into the septal arer markedly enhanced the febrile response to endotoxin in the rabbits tolerant to this pyrogen,②AVP contents in the plasma and CSF of the rabbits tolerant to endotoxin increased markedly in comparison with normal and febrile rabbits ,while in the hypothalamus it in-creased slightly in comparison with the febrile rabbits. This suggests that the centrally acting AVP may play an important role in the tolerance to endotoxin fever in rabbits.

Key words: Tolerance to endotoxin fever, Arginine vasopressin, Arginine vasopressin-antiserum, Antipyretic