Objective To observe the changes of lung and kidney aquaporin-1 expression in Lung-Qi deficiency model rats and to investigate and compare the effects of endothlin(ET)on the expression of lung and kidney aquaporin-1.It provide expremental basis to the theory of mutual relationship of lung and kidney.Method Twenty healthy rats were divided into the model group and the control group.Sample blood was taken and ET was measured by radioimmunoassay.The method of Western blot was used to observe the expression of aquaporin-1 in lung and kidney.Result The expression of aquaporin-1 in kidney was higher in model group than in the control group,while the expression of aquaporin-1 in lung was on the contrary.Compared with the control group,ET in the plasma was higher in the model group(P