Body temperature response to il-1[beta] in pregnant rats.
Simrose, Rebecca L., James E. Fewell.
Departments of Medical Physiology and Obstetrics & Gynaecology,
The University of Calgary, 3330 Hospital Drive, N.W., Calgary,
Alberta T2N 4N1, CANADA
APStracts 2:0158R, 1995.
Rats have an attenuated or absent febrile response to exogenous
pyrogen (eg, bacterial endotoxin) near term of pregnancy. With the
aim of providing insight into possible mechanism(s) of the altered
febrile response to exogenous pyrogen, experiments have been carried
out on 83 time-bred Sprague Dawley rats to investigate the febrile
response to endogenous pyrogen (ie, IL-1[beta]). On day 13 of
gestation, IV injection of IL-1[beta] produced a significant increase
in body temperature with a latency of 30 minutes and a duration of
120 minutes. In contrast, on days 17 and 21 of gestation as well as
on the day of delivery, IV injection of IL-1[beta] produced
significant decreases in body temperature. Thus, rats do not develop
fever in response to endogenous pyrogen near term of pregnancy but
rather become hypothermic. The mechanism of the altered body
temperature response to exogenous pyrogen as pregnancy proceeds
remains unknown. We speculate, however, that it most likely lies
downstream from the formation of endogenous pyrogen.
Received 25 October 1994; accepted in final form 7 June 1995.
APS Manuscript Number R616-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.