Prostaglandins

Question 1

Prostaglandins

Answer 1

Prostaglandins are a product of the Cyclo-oxygenase pathways which breaks down Arachadonic Acid. Prostaglandins act via four EP receptors: EP1, EP2, EP3 and EP4 in MDCK and these are also present but to a lesser extent in primary proximal tubule cells.

Question 2

EP1 receptor

Answer 2

EP1 receptor is involved in mediating pain by prostaglandins. There is a high number of EP1 receptors in the renal collecting ducts. There is an involvement of Ca2+ with this receptor and hence an involvement of PKC. A selective EP1 and EP3 agonist is 17-phenyl trinor. A EP1 antagonist is sc51322.

Question 3

EP2 receptor

Answer 3

EP2 receptor is involved in uterine contractions and is a relaxant in the trachea and vasculature. The extracellular loops are critical in substrate recognition. The EP2 receptor agonist used in many studies is butaprost and also PGE1 alcohol (EP2/EP4 agonist).

Question 4

EP3 receptor

Answer 4

Agonists of the EP3 receptor stimulate Gi (pertussis toxin sensitive) and inhibits adenylate cyclase. These receptors are found in the kidneys, uterus, adrenal gland, stomach. 19 (R) Hydroxy PGE1 (EP1/EP3 agonist) were used in my studies.

Question 5

EP4 receptor

Answer 5

PGE1 alcohol (EP2/EP4 agonist) was used. EP4 receptor is involved in immune cell activation and osteoblast function. This receptor is involved in the activation of adenylate cyclase. A EP4 antagonist used in my studies is L161982.

Question 6

Salt Inducible Kinase

Answer 6

This is a protein that controls the phosphorylation and subcellular localization of two kinds of transcriptional regulatory factors: class II HDACs (Histone Deacetylases) and cAMP regulated transcriptional coactivators (CRTCs).

Question 7

PGE2

Answer 7

This is the most highly expressed prostaglandin in renal proximal tubule cells.