Comparative bioassay of prostaglandin E2 and its three pulmonary metabolites

The relative potencies of prostaglandin E2 and its metabolites 15-keto PGE2, 13,14-dihydro-15-keto-PGE2 and 13,14,dihydro-PGE2 were investigated on isolated smooth muscle preparations. These were rat stomach strip, colon and uterus, chick rectum, guinea-pig ileum, trachea and pulmonary artery and rabbit aorta and pulmonary artery. 15-keto PGE2 was equiactive or 1-1.8 times more potent than prostaglandin E2 in relaxing guinea-pig trachea but otherwise the three metabolites were less active than prostaglandin E2 on all preparations.