Definition & Discovery
- Prostaglandins are unsaturated fatty acids that function as local chemical messengers in the body.
- Ulf von Euler, a Swedish biologist, discovered them in human semen in 1930. Initially assumed to be secreted by the prostate, later study found that prostaglandins are produced by a variety of cells throughout the body.
- Their activity is short-lived since they are immediately deactivated or eliminated in urine.
Physiological Roles
- Muscle contraction;
Stimulate smooth muscle contractions in the uterus, gastrointestinal tract, and blood vessels.
- Inflammation and Pain;
Act as mediators for inflammation, pain, and fever, alerting the body to injury or illness.
- Blood Clotting;
Regulate platelet aggregation, increasing clot formation or dilatation as needed.
- Cell Growth and Hormone Regulation
Play a role in controlling calcium movement, cell growth, and hormone activity.
Clinical Applications
1. Pregnancy and labour.
- PGE2 can be administered vaginally to cause uterine contractions and aid in labour.
- Misoprostol (PGE1) can be used orally or vaginally for labour induction.
- Typically, two doses are administered 4-6 hours apart to produce efficient uterine contraction.
2. Glaucoma Treatment.
- Prostaglandin analogues are used in eye drops to lower intraocular pressure, thereby preventing optic nerve injury and blindness.
- Mechanism: Relaxes muscles surrounding the eyes, increasing aqueous humour outflow.
- Side effects include stinging, burning, and increased eye pigmentation, which can darken the eyes over time.
Summary
Prostaglandins are strong, short-lived signalling molecules that control muscle contraction, inflammation, pain, and blood coagulation. Clinically, they are essential in labour induction and glaucoma therapy, albeit caution must be exercised due to potential side effects like discomfort and pigmentation changes.
