Pathophysiological changes evoked by lipopolysaccharide administration in goats.

To establish an adequate experimental model for the study of immuno-neuroendocrine mechanisms underlying the behavioral changes during the acute infection, temporal relationship of various physiological responses to endotoxin administration was examined in ovariectomized goats. Immediately after intravenous injection of 200 ng/kg of lipopolysaccharide, there were an abrupt decrease of white blood cell number and a gradual increase of rectal temperature, which were followed by elevation of plasma levels of adrenocorticotropic hormone, cortisol, glucose, free fatty acids, and then later by an increase of heart rate. The results suggest that the endotoxin administration would evoke a stereotyped cascade of, febrile, neuroendocrine and metabolic as well as autonomic response to the activation of immune systems in the ruminant species.