This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Which chemical mediator is an arachidonic acid metabolite produced by cyclo oxygenase pathway \nSelect and explain. \nA. LXA4, B. LXB4, C. 5HETE, D. PGH 2', 'role': 'user'}, {'content': 'Answer: D \nExplanation: ref Robbins 9/e p84 Prostaglandin H2 is a type of prostaglandin and a precursor for many other biologically significant molecules. It is synthesized from arachidonic acid in a reaction catalyzed by a cyclooxygenase enzyme It is acted upon by: Prostacyclin synthase to create prostacyclin Thromboxane-A synthase to create thromboxane A2 and 12-(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) (see 12-Hydroxyheptadecatrienoic acid) Prostaglandin D2 synthase to create prostaglandin D2 Prostaglandin E synthase to create prostaglandin E2 It rearranges non-enzymatically to: A mixture of 12-(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) and 12-(S)-hydroxy-5Z,8Z,10E-heptadecatrienoic acid (see 12-Hydroxyheptadecatrienoic acid) Use of Prostaglandin H2: regulating the constriction and dilation of blood vessels stimulating platelet aggregation', 'role': 'assistant'}]