Lipopolysaccharide-induced fever in Pekin ducks is mediated by prostaglandins and nitric oxide and modulated by adrenocortical hormones.
Information on avian fever is limited, and, in particular, very little is known about the mediators and modulators of the febrile response in birds. Therefore, in this study, the possible mediatory roles of nitric oxide (NO) and prostaglandins (PGs), together with a potential modulatory role for adrenocortical hormones in the generation of fever was investigated in conscious Pekin ducks. Their body temperatures were continuously measured by abdominally implanted temperature-sensitive data loggers. The febrile response induced by intramuscular injection of LPS at a dose of 100 microg/kg was compared with and without inhibition of NO production by N-nitro-L-arginine methyl ester (L-NAME), inhibition of PG synthesis (by diclofenac), and elevation of circulating concentrations of dexamethasone and corticosterone (by exogenous administration). LPS administration induced a marked, monophasic fever with a rise in temperature of more than 1 degrees C after 3-4 h. In the presence of L-NAME, diclofenac, and adrenocorticoids at doses that had no effect upon normal body temperature in afebrile ducks, there was a significant inhibition of the LPS-induced fever. In addition, during the febrile response, the blood concentration of corticosterone was significantly elevated (from a basal level of 73.6 +/- 9.8 ng/ml to a peak level of 132.6 +/- 16.5 ng/ml). The results strongly suggest that the synthesis of both NO and PGs is a vital step in the generation of fever in birds and that the magnitude of the response is subject to modulation by adrenocorticoids.
Gray
David A
DA
School of Physiology, University of the Witwatersrand, Medical School, 7 York Rd., Parktown 2193, Johannesburg, South Africa. grayd@physiology.wits.ac.za
Maloney
Shane K
SK
Kamerman
Peter R
PR
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D003345:Corticosterone / Q000097:blood / Q000627:therapeutic use*; D003907:Dexamethasone / Q000627:therapeutic use*; D004008:Diclofenac / Q000494:pharmacology; D004372:Ducks; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005334:Fever / Q000139:chemically induced / Q000188:drug therapy*; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011453:Prostaglandins / Q000378:metabolism*; D011863:Radioimmunoassay
D000893:Anti-Inflammatory Agents; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D011453:Prostaglandins; D004008:Diclofenac; D009569:Nitric Oxide; D003907:Dexamethasone; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester; D003345:Corticosterone