This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'COX 2 inhibits the following step in inflammation: \nSelect and explain. \nA. Cell adhesion, B. Cell differentiation, C. Cell migration, D. Platelet aggregation', 'role': 'user'}, {'content': "Answer: D \nExplanation: COX-1, expressed constitutively in most cells, is the dominant source of prostanoids for housekeeping functions, such as gastric epithelial cytoprotection and hemostasis. Conversely, COX-2, induced by cytokines, shear stress, and tumor promoters, is the more impoant source of prostanoid formation in inflammation. COX-2 is found in endothelial cells and inflammatory cells. In endothelial cells, COX-2 initiates the synthesis of prostacyclin, a potent vasodilator and inhibitor of platelet aggregation. Ref: Weitz J.I. (2012). Chapter 118. Antiplatelet, Anticoagulant, and Fibrinolytic Drugs. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.", 'role': 'assistant'}]