COMPARISON BETWEEN EFFECTS OF INTERLEUKIN-1-ALPHA ADMINISTRATION AND SUBLETHAL ENDOTOXEMIA IN PRIMATES

Interleukin (IL)-1 is an early mediator of host response to inflammation, although its contribution to individual components of the acute phase reaction is still unclear. To evaluate how the hemodynamic, metabolic, and hormonal responses to sublethal endotoxemia compare with IL-1 administration, baboons received intravenously either lipopolysaccharide (LPS) or 0.1, 10, or 100-mu-g/kg IL-1-alpha. LPS induced an early tachycardia and a fall in mean arterial pressure, as well as lacticacidemia and hypoaminoacidemia. Similar hemodynamic and metabolic changes were seen with 10 or 100-mu-g/kg of IL-1-alpha. An increase in adrenocorticotropic hormone and fall in serum iron were induced by IL-1-alpha but not by LPS. Plasma tumor necrosis factor-alpha-(TNF-alpha) was not measurable after IL-1-alpha-administration, whereas LPS induced a monophasic TNF-alpha-response. IL-6 levels were significantly greater after LPS than IL-1-alpha-administration. Histopathological lesions, similar in LPS- and 100-mu-g/kg IL-1-alpha-treated groups, were present only in the adrenal cortex. We conclude that many, but not all, of the effects of sublethal endotoxemia can be replicated by IL-1-alpha-administration, and these responses are dose dependent.