Role of prostaglandins and leukotrienes in the synergistic effect of oxytocin and corticotropin-releasing hormone (CRH) on the contraction force in human gestational myometrium.

We have recently demonstrated that corticotropin releasing hormone (CRH) potentiates the contractile response to oxytocin of human gestational myometrium, using a high flow microsuperfusion system and electrical field stimulation. We now report this potentiation to be equivalent to that of 1 nM prostaglandin F2 alpha (PGF2 alpha), while 10 nM PGF2 alpha did not potentiate the response to oxytocin. Prostaglandin E2 (PGE2) also showed no augmentation of the contraction force of the myometrium in response to oxytocin. The CRH potentiated response was inhibited by the lipoxygenase and cyclooxygenase inhibitor BW755C (1 microM) and by indomethacin (0.1 microM), but not by the lipoxygenase inhibitor BW4C (1 microM). Measurements of prostaglandins in the superfusate showed no significant trends. It is concluded that the potentiation of contraction force to oxytocin by CRH is dependent on prostaglandins, probably PGF2 alpha and that leukotrienes, generated via the lipoxygenase pathway are not involved.