Year Semester 2 Prostaglandins

Question 1

What are prostaglandins?

Answer 1

Polyunsaturated, oxygenated derivatives of 3 C20 fatty acids.

Question 2

What are prostaglandins classified according to?

Answer 2

1) ring code variants

2) number of double bonds in the side chain

Question 3

What is PGE2 involved in? What is attached to its R groups?

Answer 3

Inflammation

- -C=O (at the top) and OH (at the bottom)

Question 4

What is PGD2 involved in and what is attached to its R groups?

Answer 4

Immunity

- OH (at the top) and -C=O (at the bottom)

Question 5

What is PGF2𝛂 involved in and what is attached to its R groups

Answer 5

Vasoconstriction

- 2 OH groups

Question 6

What is arachidonic acid?

Answer 6

The major substrate used in PG synthesis

Question 7

What kind of PG does arachidonic acid (AA) give rise to?

Answer 7

Series 2 e.g. PGE2

Question 8

What kind of PG does dihomogamma-linolenic acid (DGLA) give rise to?

Answer 8

Series 1 e.g. PGE1

Question 9

What kind of PG does eicosapentaenoic acid (EPA) give rise to?

Answer 9

Series 3 e.g. PGE3

Question 10

What is the Omega 3 pathway?

Answer 10

Alpha linolenic acid → Octodeentetraenoic acid → Eicosatetraenoic acid → Eicosapentaenoic acid → Docosapentaenoic acid → Docosahexanoic acid

Question 11

What is the Omega 6 pathway?

Answer 11

Linoleic acid → Gamma-linolenic acid → Dihomogamma-linolenic acid → Arachidonic acid → Docosatetraenoic acid → Docosapentanenoic acid

Question 12

What is the Omega 9 pathway?

Answer 12

Oleic acid → Octadecodienoic acid → Eicosodienoic acid → Eicosotrienoic acid

Question 13

What happens when COX-1 pathway is activated?

Answer 13

TxA2 and PGI2 control platelet aggregation and vascular tone
PGE2 is involved in cytoprotection

Question 14

What happens when COX-2 pathway is activated?

Answer 14

pro-inflammatory PGs are synthesised

Question 15

What are PGs involved in?

Answer 15

Fever generation 
Ovulation, fertilisation & parturition
GI function
Renal function 
Carcinogenesis
Bone remodelling 
Sleep
Inflammation and pain 
Allergy and immunity 
Vascular homeostasis and haemostasis

Question 16

What are PG receptors and what are they linked to?

Answer 16

G protein coupled transmembrane receptors, they are linked to cAMP and Ca2+ signalling

Question 17

What does the EP1 receptor mediate?

Answer 17

GI contraction and pyrexia

Question 18

What does the EP2 receptor mediate?

Answer 18

Bronchodilation, vasodilation and GI fluid secretion

Question 19

What does the EP3 receptor mediate?

Answer 19

GI relaxation, inhibition of gastric acid secretion, inhibition of ANS transmitters and pyrexia

Question 20

What does the EP4 receptor mediate?

Answer 20

vasodilation, bone homeostasis & pyrexia

Question 21

What are the ways in which PGs can be used therapeutically?

Answer 21

Substrate substitution
Enzyme inhibition
Replacement therapy

Question 22

What is the role of PGE2 in cancer?

Answer 22

It is proliferative, too much of it isn’t good for the body. Cancer cells produce high amounts of PGE2.

Question 23

What does a decrease in PGE2 lead to (terms of renal syndromes caused by the effect of NSAIDs)?

Answer 23

↑ Na retention 
Peripheral edema
↑ blood pressure
↑ weight 
Congestive heart failure

Question 24

What does a decrease in PGI2 lead to (terms of renal syndromes caused by the effect of NSAIDs)?

Answer 24

Hyperkalaemia

Acute renal failure

Question 25

Give examples of 2 PGF𝛂2

Answer 25

Latanoprost

Bimatoprost

Question 26

What can a derivative of PGF𝛂2 do to intra-ocular pressure?

Answer 26

It can reduce intra-ocular pressure relieving the optic nerve - the allows fluid to drain freely.