[Effect of castor oil-diet on the initiation of labor of pregnant rat].

OBJECTIVE: This study was designed to explor the effect of castor oil-diet, on the intiation of labor of preganant rat and determine what the active component of castor oil-diet was. METHODS: The time of the intiation of labor and course of delivery were observed by gavaged rats castor oil-diet at 18, 19 and 20 days of gestation. The compositions of fat acid of castor oil-diet and castor oil were analyzed by HPLC. RESULTS: The castor oil-diet could induce the initiation of labor and shorte the course of the delivery in pregnant rats. Ricinoleic acid was the active component of castor oil-diet in this study. CONCLUSIONS: Pregnant rats by gavaged castor oil-diet could serve as the animal model for induction of labor. Ricinoleic acid is likely the chief component to the induction of labor.