<prompt> Which chemical mediator is an arachidonic acid metabolite produced by cyclo oxygenase pathwayLXA4LXB45HETEPGH 2  <response>: ref Robbins 9e 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 