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This Article Full Text Full Text (PDF) All Versions of this Article: 91/4/741    most recent expphysiol.2006.033688v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Moore, S. L. Articles by Fewell, J. E. Search for Related Content PubMed PubMed Citation Articles by Moore, S. L. Articles by Fewell, J. E. Related Collections Placental-Perinatal

¹ Department of Physiology & Biophysics, University of Calgary, Health Sciences Centre, 3330 Hospital Drive NW, Calgary, Alberta T2N 4 N1, Canada

Pregnancy alters the cytokine, prostanoid and core temperature responses of rats to infectious stimuli at a time when blood levels of the endogenous glucocorticoid corticosterone are elevated. Given that glucocorticoids attenuate bacterial pyrogen-induced fever in rats, the present experiments were carried out to test the hypothesis that administration of RU38486, a glucocorticoid type II receptor antagonist, would restore the febrile response to E. coli lipopolysaccharide (LPS) in pregnant rats on day 21 of gestation. Pregnant rats were randomly allocated to one of four experimental groups depending upon whether they received RU38486 (20 mg kg^–1 intragastric) or vehicle followed by E. coli LPS (160 µg kg^–1I.P.; a minimal dose that elicits maximal febrile response in non-pregnant rats) or vehicle. Basal core temperature was not altered by intragastric administration of RU38486 or vehicle. Following intragastric administration of vehicle, intraperitoneal administration of E. coli LPS produced a significant hypothermia with latency, duration and magnitude of 0.5 h, 2 h and –1.3°C, respectively. Following intragastric administration of RU38486, however, intraperitoneal administration of E. coli LPS elicited only a minimal decrease in core temperature which was not significantly different from control values. Thus, our data provide evidence that endogenous glucocorticoids play a role in modulating the early core temperature response to a relatively large dose of bacterial pyrogen in rats at term of pregnancy.

(Received 17 February 2006; accepted after revision 26 April 2006; first published online 27 April 2006)
Corresponding author J. E. Fewell: Heritage Medical Research Building 206, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4 N1, Canada. Email: fewell{at}ucalgary.ca.