Abstract： Objective To investigate the changes in circulatory and pulmonary monary angiotensinⅡin rats with acite lung injury(ALI)and explore the role of angiotensinⅡin ALI.Method Thirty S-D rats were randomly divided into control group(n=6)and ALI group(n=24).The ALI group was further divided into four subgroups of observation at various intervals,3,6,9 and 12 hours after administration of lipopolysaccharide (LPS)into the femoral vein(each n=6).The indices rate,blood gas analysis,wet weight/dry weight(W/D)ratio of lung lobes,and pathological changes were successively observed at 3,6,9,and 12 hours after injury.The content of angiotensinⅡin lung tissue and blood plasma were detected at above set intervals by radioimmunoassay.Data of these assays were analyzed by one-factor analysis of variance.Results Compare with the control group,pH and PaO2 of arterial blood in ALI group decreased significantly(P＜0.05)at all intervals and PaCO2 of arterial blood in ALI group decreased significanfly(P＜0.05).at all intervals and PaCO2 of arterial blood and lung W/D weight ratio increased significantly(P＜0.05),and scores of lung histopathology denoted the lung injuried(P＜0.01).After injury of lung,angiotensin Ⅱ content increased markedly in lung homogenate and blood plasma (P＜0.05).Angiotensin Ⅱ content in blood plasma reached peak value at 9 hours,and content of angiotensin Ⅱ in lung homogenates kept on increasing at allintervals of observation.Conclusions A large amount of angiotensin Ⅱ releases into lung tissue and blood plasma during ALI,suggesting systemic and pulmonary rennin-angiotensin systems are activated.