COX 2 regulates inhibits: (LQ)
a. Prostanoids (20 carbon compounds) are the product of cyclooxygenase (COX) metabolism.
b. COX is synthesized by endothelial cells. At present, there are 3 isoforms of COXs: 1,2,3. COX-1 is a constitutive enzyme: that means, it is physiological while COX-2 is pathological.
c. However, COX-2 too plays some physiological role. COX-3 is an anti-inflammatory enzyme.
d. It has been proposed that if we could have drugs that can stimulate the activity of COX-3, we shall anti-inflammatory prostaglandins produced whose potency can be more than even that of corticosteroids. COX-2 has increasingly been known to physiologically relevant.
e. It has been shown to affect cellular differentiation in tumors, bone marrow cells, bone cells (osteoblasts), embryonic cells, kidneys and gut mucosa cells.
f. This has fueled fears for quite sometime that COX-2 inhibitors will be teratogenic if they are used in pregnancy. However, it remains to be clinically seen.
Since, selective block of COX-2 has been known to potentiate cardio and vascular events; drugs like rofecoxib has been banneD. Valdycoxib has also been banned because of the same plus due to high incidence of allergic reactions.