Eicosanoids

Question 1

List 5 types of Eicosanoids

Answer 1

Prostaglandins, Prostacyclins, Thromboxanes, Leukotrienes, Lipoxins

Question 2

Where are arachidonic acids derived from and by what action are they derived?

Answer 2

Arachidonic acid is released from membrane phospholipids via phopholipase A2.

Question 3

What is the rate limiting step in prostaglandin synthesis?

Answer 3

Hydrolysis of arachonic acid

Question 4

How do agents of prostaglandin production function?

Answer 4

Stimulate production by stimulating activity of phosphlipase A2

Question 5

What is the first prostaglandin product?

Answer 5

PGH2

Question 6

What are the 2 components of prostaglandin sythesis?

Answer 6

COX (cyclooxygenase) and PG hydroperoxidase (requires GSH)

Question 7

COX-1 Enzyme

Answer 7

Constitutive (always in constant amount). Found in gastric mucosa, platelets, vascular endothelium, and kidney

Question 8

COX-2 Enzyme

Answer 8

Inducible. Mainly in activated macrphages/monocytes stimulated by PAF, IL-1, or bacterial lipopolysaccharides. Also in smooth muscle cells. Epithelial/ondothelial cells, and neurons.

Question 9

What inhibits COX2 induction?

Answer 9

Glucocorticoids

Question 10

What inhibits COX enzymes?

Answer 10

NSAIDS (more type 2 than 1)

Question 11

Aspirin’s MOA

Answer 11

inhibits COX1 more than 2. Involves acetylation of the COX enzyme

Question 12

Steroidal anti-inflammatory drug MOA

Answer 12

inhibit phospholipase A2 activity

Question 13

Major prostaglandins of blood vessels

Answer 13

PGI2 and PGF2

Question 14

What is an important inhibitor of platelet aggregation?

Answer 14

PGI2

Question 15

Major prostaglandin produced by platelets

Answer 15

Thromboxane

Question 16

Actions of prostaglandins

Answer 16

mediators of inflammation, induce redness and heat, increase capillary permeability, pyrogens activate sythesis of prostaglandins, stimulate uterine contraction, inhibit gastric acid secretion

Question 17

What are the products of lipoxygenases?

Answer 17

HPETEs

Question 18

What is another name for HETEs?

Answer 18

leukotrienes

Question 19

What is the most important product of human lipoxygenases?

Answer 19

5-HPETE, because they are converted into leukotrienes

Question 20

Important secretory product of leukocytes

Answer 20

Leukotrienes

Question 21

Leukotrienes’ role in inflammatory disorders

Answer 21

mediates inflammatory disorders

Question 22

Which leukotrienes increase vascular permeability

Answer 22

LTB4, LTC4, LTD4, LTE4 (B thru E increase permeability)