ROLE OF EICOSANOIDS IN THE REGULATION OF THE PERIPARTURIENT PERIOD INCATTLE

In this review, the role of eicosanoids in regulation of parturition a nd the postpartum period was described with special emphasis on the bo vine species. The metabolism of arachidonic acid and the production of eicosanoids during the peripartum period was discussed. Prostaglandin E2 and F2alpha (PGE2, PGF2alpha) play an important role in mechanisms controlling parturition. They are involved in luteolysis, uterine con tractions and dilation of the cervix. Eicosanoids also seem to influen ce the loosening processes of the fetal membranes. However, in the lit erature, conflicting results were found. Many investigations suggested that retained placental membranes could be related to low PGF2alpha p roduction and/or an imbalance of arachidonic acid metabolism in the ut erus. The possible role of the lipoxygenase pathway metabolite 15-hydr oxy-eicosatetraenoic acid (15-HETE) in expulsion of the fetal membrane s was also discussed. As far as the postpartum period is concerned, a relationship between postpartum PGF2alpha release and the involution o f the uterus was found. Cows with undisturbed uterine involution had h igher PGF2alpha production than cows with delayed involution. In contr ast to the positive effect of PGF2alpha on uterine involution, PGE2 se ems to delay the involution processes. Further experiments are necessa ry in order to study the function of eicosanoids in mechanisms regulat ing parturition, release of the fetal placental membranes and involuti on of the uterus.