Isoproterenol prevents oxidant-induced injury in isolated rabbit lungs

Increased vascular permeability in the adult respiratory distress syndrome is due in part to toxic oxygen metabolites. In the present study, we produced lung injury in the isolated rabbit lung with hydrogen peroxide (H₂O₂) and examined its prevention with isoproterenol. Pulmonary arterial pressure (Ppa) and the fluid filtration coefficient (Kf) were measured as indices of lung injury. Rabbits were divided into two groups, and 7 mmol/1 H₂O₂ was administered in both groups. In one group, isoproterenol (2 ug/ml) was administered 10 min before H₂O₂ injury. Ppa increased transiently after H₂O₂ administration in the control group but was unchanged in the isoproterenol group. Kf was significantly increased by H₂O₂ administration in the control group but not in the isoproterenol group. We conclude that H₂O₂ increases pulmonary vascular permeability and that isoproterenol may protect against H₂O₂-induced pulmonary injury.