Prostaglandins are hormones that are produced locally and can also act locally in the reproductive system, blood vessels, gastrointestinal tract, endocrine system and respiratory system. 1. Reproductive system: Prostaglandins can maintain the contraction of smooth muscle of male reproductive organs, which has a great relationship with ejaculation. 2. Blood vessels: prostaglandins can dilate blood vessels, thereby reducing peripheral resistance to blood flow and lowering blood pressure. 3. Gastrointestinal tract: prostaglandins can cause smooth muscle contraction, inhibit the secretion of gastric acid, and have a protective effect on cells. 4. Endocrine system: prostaglandins have a certain effect on the content of cyclic adenosine monophosphate in endocrine cells, thus affecting the synthesis and release of hormones. 5. Respiratory system: prostaglandins can relax the smooth muscle of bronchial tubes, reduce the resistance of airways, and favor ventilation.