Overview of Prostaglandin Research 1999.4.23

Overview of Prostaglandin Research 1999.4.23

When the skin is damaged, local prostaglandins are secreted, leading to four pathological changes: redness, heat, swelling, and pain. Aspirin can inhibit the secretion of prostaglandins, thereby alleviating local symptoms. In the 1930s, GolGPatl and Enlel discovered a substance in human semen that had both hypotensive and uterine-stimulating effects. At the time, it was believed that this substance was produced by the prostate, hence the name "prostaglandin" (PG). In the 1960s, biochemical studies conducted in various regions showed that PG is not exclusively produced by the prostate but is widely present throughout the body, acting as an active substance with numerous biological effects. Subsequently, series of prostaglandins such as PGE and PGD were synthesized. In the mid-1970s, it was discovered that platelets and vascular walls can respectively synthesize two prostaglandins with opposite effects: ① thromboxane A₂ (TXA₂); ② prostacyclin (PGL₂). Since then, research on PG has flourished worldwide, hailed as a major event in the international medical community of the 20th century. PG is primarily released locally and exerts its effects locally, which is a characteristic that distinguishes PG from other endocrine hormones. PG serves as a local regulator of cellular functions, and this regulation is achieved through neurotransmitters and neural reflexes. Although prostaglandins produced by different tissues have similar structures, their functions vary greatly. Each organ and tissue produces PG with its own specific function, and interactions between different PGs often result in either promotion or antagonism. Therefore, the effects of PG should be understood individually rather than generalized.

1. Obstetrics and Gynecology

PGE is a potent stimulant of the pregnant uterus, making it useful for inducing abortion, labor induction, oxytocin stimulation, and contraception. In particular, contraception is currently a topic of great interest.

2. Cardiovascular Medicine

Because thromboxane (TXA₂) and prostacyclin (PGL₂) have completely opposite properties, they work together to maintain the integrity and patency of blood vessels. It has now been found that the serum levels of PGL₂ are reduced in patients with hypertension. Animal experiments have demonstrated that PGL₂ has a powerful vasodilatory effect. Clinical trials have also confirmed the hypotensive effect of PGL₂. Furthermore, the coronary vasodilatory effect of PGL₂ has been clinically verified, relieving angina pectoris and protecting the myocardium of patients with myocardial infarction. Cerebral infarction is believed to occur when TXA₂ increases and PGL₂ decreases. Since TXA₂ has an extremely short half-life—only 30 seconds—it quickly converts into TXB₂. Therefore, the higher the concentration of TXB₂, the lower the concentration of PGL₂, making cerebral infarction more likely. Thus, using PGL₂ can help prevent cerebral infarction.

3. Respiratory Medicine

Prostaglandins are widely present in the bronchi and lungs, including PGE, PGE₂, and PGE₂a. Externally, PGE has a strong vasodilatory effect, while PGF has the opposite effect. Asthma patients often have higher levels of PGF than normal individuals, and the effect of PCE is 5 to 100 times stronger than that of isoprenaline, with a longer duration. PCE is also highly effective in treating adult respiratory distress syndrome (ARDS).

4. Gastroenterology

In the stomach, PG can weaken Hp activity, reduce gastric acid secretion, and strengthen intestinal peristalsis in those with weak motility while weakening it in those with strong motility. Overall, the regulation of the digestive tract tends toward homeostasis.