Document Detail


Influence of pregnancy on plasma cytokines and the febrile response to intraperitoneal administration of bacterial endotoxin in rats.
MedLine Citation:
PMID:  14603373     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Rats have an attenuated febrile response to exogenous (e.g. bacterial endotoxin) and endogenous pyrogen (e.g. interleukin-1beta) near the term of pregnancy, the mechanism of which is unknown. The present experiments were carried out on 71 non-pregnant and 181 pregnant Sprague-Dawley rats to determine if basal levels of the endogenous antipyretic substance, interleukin-1 receptor antagonist (IL-1ra), change relative to interleukin-1beta (IL-1beta) throughout gestation. Furthermore, we have constructed complete Escherichia coli lipopolysaccharide (LPS) dose-core temperature response curves in non-pregnant and pregnant rats on days 10, 15 and 20 of gestation (term of gestation approximately 21 days) to determine if the attenuated febrile response near the term of pregnancy results from a simple shift of the dose-response relationship or results from a dampening of the overall dose-response relationship. Basal IL-1beta, as determined by ELISA on trunk blood from non-pregnant and pregnant rats on days 10, 15 and 20 of gestation (d10, d15, d20), did not change significantly during pregnancy. Basal IL-1ra, however, was increased significantly in d15 rats as compared to non-pregnant, and d10 and d20 rats. The attenuated febrile response near the term of pregnancy, as determined by biotelemetry, did not result from a simple shift of the E. coli LPS dose-core temperature response curve but rather a dampening of the overall dose-response relationship. The febrile responses to EC(50) and EC(100) doses of E. coli LPS were preceded by a period of hypothermia, and were delayed and attenuated near the term of pregnancy as compared to that observed early in pregnancy and in non-pregnant rats. Our data provide evidence that pregnant rats are more sensitive to the hypothermia-producing effects of E. coli LPS than are non-pregnant rats and allow us to speculate that elevated basal IL-1ra may play a role in mediating the attenuated febrile response to pyrogen on day 15 but not on day 20 of gestation in rats.
Authors:
Anita E Fofie; James E Fewell
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental physiology     Volume:  88     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2003 Nov 
Date Detail:
Created Date:  2003-11-06     Completed Date:  2004-07-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  747-54     Citation Subset:  IM    
Affiliation:
Department of Physiology and Biophysics, University of Calgary, Health Sciences Centre, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / drug effects
Animals
Body Temperature / drug effects*
Dose-Response Relationship, Drug
Endotoxins / administration & dosage
Escherichia coli
Female
Fever / blood,  chemically induced*,  physiopathology*
Injections, Intraperitoneal
Interleukin 1 Receptor Antagonist Protein
Interleukin-1 / blood*
Lipopolysaccharides / administration & dosage*
Models, Animal
Pregnancy
Pregnancy, Animal / blood*
Rats
Rats, Sprague-Dawley
Sialoglycoproteins / blood*
Chemical
Reg. No./Substance:
0/Endotoxins; 0/Interleukin 1 Receptor Antagonist Protein; 0/Interleukin-1; 0/Lipopolysaccharides; 0/Sialoglycoproteins

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