[The antioxidative chromane structure of alpha-tocopherol protects against the consequences of arachidonic acid release in the pulmonary vascular bed (author's transl)].

In the model of isolated, ventilated and perfused rabbit lungs release of arachidonic acid results in an increase of pulmonary vascular resistance and permeability. The former can be ascribed to cyclooxygenase products, the latter to lipoxygenase products of arachidonic acid. The effect of alpha-tocopherol on the increase of pulmonary vascular resistance and permeability either after the addition of arachidonic acid to the perfusion fluid or after stimulation of arachidonic acid liberation by Ca-ionophore A 23187 was investigated. It is possible to distinguish a membrane effect of the phytol side chain of alpha-tocopherol and an antioxidative effect of its chromane structure: Phytol augments the increase of pulmonary vascular resistance and permeability, whereas the chromane-structure decreases both to a large degree. The possibility of antioxidative therapy in disturbances of pulmonary vascular permeability is discussed.