This document outlines the topics covered in a lecture on prostaglandins. The lecture will discuss an overview of prostaglandins, the different types of prostaglandins, their biosynthesis from arachidonic acid, inhibition of their synthesis, their biochemical actions including effects on blood pressure, inflammation, reproduction, and more. The lecture will also cover the biomedical applications of prostaglandins such as induction of labor and treatment of peptic ulcers.

1. DR SHAMIM SHAIKH MOHIUDDIN
DEPARTMENT OF BIOCHEMISTRY
UNIVERSITY OF DAMMAM
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2. Outline of this lecture topics………
1. Overview of prostaglandins (slide no 3)
2. Different Types of Prostaglandins (slide no 4)
3. Biosynthesis of Prostaglandins (slide no 5)
4. Inhibition of Prostaglandins synthesis (slide no 7)
5. Biochemical actions of Prostaglandins (slide no 8)
6. Biomedical application of Prostaglandins (slide no 11)
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3. -Prostaglandins (PGs) and related compounds ie
Prostacyclines (PGI), Thromboxanes ( TXA), Leukotrienes
( LT) and Lipoxins are collectively known as eicosanoids.
-Most are produced from arachidonic acid, a 20-carbon
polyunsaturated fatty acid (5,8,11,14-eicosatetraenoic
acid).
-The eicosanoids are considered "local hormones." as……
-They have specific effects on target cells close
to their site of formation.
-They are rapidly degraded, so they are not
transported to distal sites within the body.
Overview of prostaglandins
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4. Outline of different types of Prostaglandins
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5. Cell Membrane Phospholipids
Phospholipase A2
Arachidonic Acid
Prostaglandin G2 ( PGG2)
Cyclooxygenase 1 &
2
Thromboxane A2Prostacyclin (PGI2)
Prostaglandin F2α ( PGF2α) Prostaglandin E2 (PGE2)
Prostaglandin H2 ( PGH2)
PGI2
synthase
reductase
TXA2
synthase
isomerase
peroxidase
Biosynthesis of Prostaglandins
CORTICOSTEROIDS
ASPIRIN
INDOMETHACIN
IBUPROFEN
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6. -Arachidonic acid(5,8,11,14 –eocosatetraenoic
acid) is the precursor for most of the
prostaglandins in human.
-It occurs in the endoplasmic reticulum in the
following stages……
1. Phospholipase A2 release arachidonic acid
from membrane bound phospholipids. Hormones
such as epinephrine or bradykinin stimulates
this reaction.
2. Oxidation and cyclization of arachidonic
acid to PGG2 by cyclooxygenase 1 & 2
3. PGG2 is then converted to PGH2 by a
reduced glutathione dependent peroxidase.
4. PGH2 serve as immediate precursor for
synthesis of different types of prostaglandins 6

7. Inhibition of Prostaglandin synthesis
Following compounds can inhibits prostaglandin synthesis by
following mechanism……
1.Corticosteroids- Prevent the formation of Arachidonic
acid by inhibiting Phospholipase A2
2.Aspirin-Irreversible inhibitor the enzyme Cyclooxygenase
3.Indomethacin- Reversible inhibitor of the enzyme
cyclooxygenase
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8. Biochemical actions of Prostaglandins
1.Regulation of blood pressure
PGE2 and PGI2 are vasodilators in vascular bed
Increased blood flow and decrease peripheral resistance
Lower blood pressure
2. Inflammation
PGE1 and PGE2 induce the symptoms of inflammation
(redness, swelling etc.) due to vasodialation
3. Reproduction
PGE2 and PGF2α causes contraction of uterine smooth
muscle in pregnant woman
results in
leads to
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9. 4. Pain and fever
Pyrogens (fever producing agent) promotes prostaglandin
biosynthesis
Formation of PGE2 in hypothalamus
Fever associated with pain
5. Regulation of gastric secretion
-Prostaglandins inhibit gastric secretion
-Prostaglandins stimulate pancreatic secretion and
increase the motility of intestine
diarrhea
Leads to
causes
causes
6. Influence on immune system
PGE decreases on immunological functions of B and
T lymphocytes
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10. 7. Effect on respiratory function
-PGEs causes bronchial smooth muscle relaxation
-PGFs causes bronchial smooth muscle constriction
PGE and PGF oppose the actions of each other in the lung
8. Influence on renal function
Prostaglandin increases glomerular filtration rate (GFR)
Promotes urine output
thus
thus
9. Effect on platelet aggregation
-PGI2 inhibits platelet aggregation
-Thromboxane (TXA2) and PGE2 promotes platelet
aggregation and blood clotting that might leads to
thrombosis 10

11. BIOMEDICAL APPLICATION OF PROSTAGLANDINES
1. Induction of labor at term.
Induction of labor is produced by:
-infusion of PGF2a (carboprost tromethamine)
-PGE2 (dinoprostone)
2.Treatment of peptic ulcer.
Misoprostol [Cytotec]
-a methylated derivative of PGE1
-is approved for use in patients taking high
doses of nonsteroidal antiinflammatory drugs
(NSAIDs) to reduce gastric ulceration.
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