<prompt> True about COX2 are all EXCEPT :It is constitutionally expressed on some cell surfacesActivation of COX2 leads to ulceroprotective effect on gastric mucosaInduced at the site of inflammationIt is utilized in generation of eicosanoids with a ring structure  <response>: COX-2 is constitutively active within kidney, endothelium and brain. Recommended doses of COX-2 inhibitors cause renal toxicities similar to those associated with other NSAIDs.COX-2 inhibitors have been shown to have less gastrointestinal side effects because COX-1 is mainly involved in protection from gastric ulcers.Constitutive COX-1 isoform tend to be house keeping in function while COX-2 is induced during inflammation.COX have role in synthesis of PGs from arachidonic acid, PGs have 20C fatty acids containing cyclopentane ring.Selective COX-2 inhibitors increase the risk of MI. 