What Are the Main Functions of Prostaglandin in the Human Body?
Any of a group of physiologically active substances having diverse hormonelike effects in animals are called prostaglandin. It was very first discovered in human semen in 1935 by the Swedish physiologist Ulf von Euler. He named it prostate because he thought that they were secreted by the prostate gland.
Further, a detailed study on the prostate gland was done in the 1960s to 1970 by Swedish biochemists Sune K. Bergström and Bengt Ingemar Samuelsson and British biochemist Sir John Robert Vane. All three of them were awarded the Nobel prize for their study.
Prostaglandin Synthesis
Prostaglandins are made up of unsaturated fatty acids that contain a cyclopentane ring i.e. 5-Carbon ring and they are derived from 20-carbon, straight-chain, polyunsaturated fatty acid precursor arachidonic acid. Here arachidonic acid is a key component of phospholipids, which itself is an integral component of the cell membrane.
There are so many activities that cause the formation and release of prostaglandin like different stimuli, including various hormonal, chemical, or physical agents, a chain of events is set in motion. All these stimuli lead to the activation of an enzyme called phospholipase A2 either in a direct or indirect way. Further, this enzyme helps in catalysing the release of arachidonic acid from phospholipid molecules.
Based on the stimulus type and presence of different enzymes, there is a divergence of the pathway of arachidonic acid.
Functions of Prostaglandins
Some of the major function of prostaglandins are listed below:
A. In plants also, they synthesize molecules similar in structure to prostaglandins, including jasmonic acid which help in processing functions like plant reproduction, fruit ripening, and flowering.
B. Level or concentration of prostaglandins affect the level of blood pressure.
C. Due to structural differences present in prostaglandin affect different biological activities of the body.
D. Some prostaglandin work in autocrine fashion, stimulating reactions in the same tissue in which they are synthesized, and others act in a paracrine fashion.
E. Prostaglandin also mediates functions like inflammatory or anti-inflammatory processes and therefore that can be harmful or not harmful.
F. They also participate in functions like contraction and relaxation of smooth muscle, the dilation and constriction of blood vessels.
G. Prostaglandin also shows effect on influencing the release of adrenergic neurotransmitters from nerve endings, possibly by a direct mechanism.
Prostaglandins Examples
There are different types of prostaglandins, they are: including prostaglandin I2 (prostacyclin; PGI2), prostaglandin D2 (PGD2), prostaglandin E2 (PGE2), and prostaglandin F2α (PGF2α). Each of these have their specific function.
Function of different Prostaglandins are:
A. Prostaglandin I2:
They perform functions like vasodilation, also inhibit platelet aggregation, bronchodilation.
B. Prostaglandin D2:
They are majorly produced by mast cells; recruits Th2 cells, eosinophils, and basophils and they majorly critical to development of allergic diseases such as asthma.
C. Prostaglandin E2:
They perform smooth muscle contraction of the gastrointestinal tract.
D. Prostaglandin F2α:
Their secretion helps in uterus contraction and urinary bladder contraction.
FAQs on Prostaglandin: Key Roles, Synthesis, and Biological Importance
1. What are prostaglandins and what is their primary role in the body?
Prostaglandins are special lipid compounds that function like local hormones, meaning they act on cells near where they are produced. Their main role is to respond to illness or injury. They are key players in processes like causing inflammation, blood clot formation, fever, and the induction of labour.
2. Where are prostaglandins produced in the body?
Unlike most hormones which are made in specific glands, prostaglandins are synthesised in almost all nucleated cells throughout the body. They are created on-demand right at the site of tissue damage or infection, which is why they are often called 'local hormones'.
3. What are some of the main medical uses of prostaglandins?
In medicine, synthetic prostaglandins are used for several important reasons. Their applications include:
- Inducing childbirth or for therapeutic abortions.
- Treating stomach ulcers by protecting the stomach lining.
- Managing glaucoma by reducing pressure inside the eye.
- Keeping a vital blood vessel open in newborns with specific heart conditions.
4. What situations trigger the body to release more prostaglandins?
The body releases prostaglandins mainly in response to cell damage or stress. Common triggers include physical injuries like cuts and bruises, infections from bacteria or viruses, and as part of the inflammatory response during an allergic reaction.
5. Are prostaglandins considered true hormones? Explain the key difference.
No, prostaglandins are not considered true hormones, though they have hormone-like effects. The key difference is that true hormones are produced in endocrine glands, travel through the bloodstream to distant targets. In contrast, prostaglandins are produced by almost any cell and act locally on nearby cells, without entering the bloodstream in large amounts.
6. How exactly do prostaglandins cause the feelings of pain and inflammation?
When you get injured, cells in that area release prostaglandins. These compounds increase the sensitivity of your local pain receptors, making you feel pain more intensely. They also cause blood vessels to dilate and become leaky, which results in the classic signs of inflammation—swelling, redness, and heat—as your body begins the healing process.
7. How do common painkillers like aspirin or ibuprofen work in relation to prostaglandins?
Common painkillers, also known as NSAIDs (Nonsteroidal Anti-Inflammatory Drugs), work by blocking an enzyme called cyclooxygenase (COX). This enzyme is essential for producing prostaglandins. By inhibiting this enzyme, drugs like aspirin and ibuprofen effectively stop the production of prostaglandins, thereby reducing pain, fever, and inflammation.
8. Can different prostaglandins have opposite effects?
Yes, absolutely. This is one of their most interesting features. For example, some types of prostaglandins (like thromboxanes) promote blood clotting, while others (like prostacyclin) inhibit it. Similarly, some can cause blood vessels to constrict while others cause them to dilate. This allows for very precise and balanced control over bodily processes.
