Abstract
. The release of prostaglandin E1 from the rat phrenic nerve‐diaphragm preparation during tetanic contraction of the muscle in response to nerve stimulation is reported. Tentative identification of the prostaglandin depended on solvent extraction column and thin‐layer chromatography and parallel biological assay. . Polar lipid substances were released from the preparation in the absence of nerve stimulation by (+)‐tubocurarine and noradrenaline. . The output on nerve stimulation was not abolished by (+)‐tubocurarine, hemicholinium, bretylium or phenoxybenzamine added to the bath. . The possible origin of these prostaglandins is discussed.