Objective:To investigate the equilibrium of vasomotor function and the prevention of lipid peroxidation of leonurine(Leo) on pituitary(Pit)-induced acute myocardial ischemia injury in rats.Methods: Pit was administrated intraperitoneally to induce acute myocardial ischemia injury in rats.The concentration of endothelin(ET) in plasma and myocardium were measured by radio immunoassay.The level of nitric oxide(NO)

the activity of superoxide dismutase(SOD) and the content of malondialdehyde(MDA) in serum and myocardium was determined by nitrate reductase assay

xanthine oxidase assay and thibabituric acid assay

respectively.Results: Within certain dose range of Leo

the contents of ET and MDA were obviously decreased and the level of NO and the activity of SOD were increased.Linear regression analysis(scatterplot) indicated that there was dose-effect relationship of Leo against myocardial ischemia injury within certain dose range.Conclusions:Leo inhibits Pit-induced myocardial ischemia injury.The mechanism may be related to the equilibrium of vasomotor function and the prevention of lipid peroxidation.