Effects of some prostaglandin E1 analogues on guinea pig and human respiratory tract

The effects of (a) 4, 5, 6-trinor-3, 7-inter-m-phenylene PGE1 methyl ester, (b) 4, 5, 6 trinor-3, 7-inter-m-phenylene 3 oxa PGE1 and (c) 4, 5, 6 trinor-3, 7-inter-m-phenylene 3 oxa PGE1 methyl ester on human and guinea pig respiratory tract muscle in vitro and in vivo have been studied. All the analogues relaxed the isolated preparations of guinea-pig tracheal chain, human tracheal, bronchial and bronchiolar muscles and decreased histamine-induced lung resistance in the anaesthetised guinea pig. On some preparations the effects of the analogues were more pronounced than those of PGE1. The results suggest that some of the inter-m-phenylene analogues of PGE1 may be bronchodilators in asthmatics.