Prostaglandin High level of estrogen and HCG activiated arachidonic acid.Arachidonic acid transformed to epoxidase Promoted prostaglandin secretion ·Histamine increased Increased the permeability of capillary Hydrothorax and ascite 9Prostaglandin • High level of estrogen and HCG activiated arachidonic acid. Arachidonic acid transformed to epoxidase • Promoted prostaglandin secretion • Histamine increased • Increased the permeability of capillary • Hydrothorax and ascite 9