Corticotropin-releasing hormone increases prostaglandin F2 alpha activity on human myometrium in vitro

OBJECTIVE: Our purpose was to study the capability of synthetic corticotropin-releasing hormone to directly stimulate human myometrium and to modulate the activity of prostaglandins F2 alpha and E2. STUDY DESIGN: Strips from human myometrium were obtained from 127 elective cesarean sections at term. The in vitro effect of human rat corticotropin-releasing hormone on myometrial contractility has been studied in resting myometrial strips mounted in a two-chamber bath for isolated organs. Stimuli (corticotropin-releasing hormone, prostaglandins F2 alpha and E2, and oxytocin) were administered as one single dose in the perfusion chamber. In each experiment one myometrial strip was used as a control. RESULTS: Corticotropin-releasing hormone significantly increases (p < 0.01) the myometrial response to prostaglandin F2 alpha. The hormone neither has a direct inotropic effect nor is it able to enhance the effect of prostaglandin E2 and oxytocin on myometrial strips. CONCLUSION: The positive effect of corticotropin-releasing hormone on the myometrial response to prostaglandin F2 alpha adds new support to the theory that placental corticotropins may modulate the onset of labor.