Question

40. How can inhibiting the activation of phospholipase A2 impact eicosanoid biosynthesis? Release of arachidonic acid by phospholipase A2 is the first step in the pathway b. Drugs that inhibit phospholipase A2 stimulate the synthesis of eicosanoids c. Inhibiting phospholipase A2 could favor the synthesis of prostaglandins d. Inhibitors of phospholipase A2 can only block the synthesis of leukotriene's

Answer 1

Correct Option

a. Release of arachidonic acid by phospholipase A2 is the first step in eicosanoid biosynthesis

Wrong Options (Explanation)

b. Phospholipase A2 is an intracellular protein which cleaves phospholipids producing lysophospholipids and free fatty acids. It is involved in the production of free fatty acids, such as arachidonic acid. Drugs that inhibit phospholipase A2 donot stimulate the synthesis of eicosanoids (prostaglandins, leukotrienes, and thromboxanes). Because eicosanoids are derived from arachidonic acid, inhibiting phospholipase A2 will inhibit synthesis of eicosanoids.

c. Release of arachidonic acid (AA) is considered as the rate-limiting step in prostaglandins (PG) biosynthesis. As mentioned earlier, inhibiting phospholipase A2 will inhibit release of AA. thus inhibiting PG biosynthesis.

d. Inhibitor of phospholipase can inhibit synthesis of other eicossanoids such as thromboxanes and prostaglandins also. Because the first stepn carried by phospholipase A2 is common to all eicosanoids biosynthesis.

Iillll!! ! ! ! ! ! a Membrant Az P44, — Cox cox | (Phospholipase Arachidonic - Acid 15-Lox PGH2 5-HPETE 5-HETE Thronboxanes - Leukotrienes Yfostaglandins