12(R)-HETE is an endogenous active metabolite of the ω-6 PUFA and eicosanoid precursor arachidonic acid.^1,2 It is formed from arachidonic acid by 12R-lipoxygenase (12R-LO), as well as cytochrome P450s (CYPs). 12(R)-HETE binds to the TP receptor in washed isolated human platelets (IC50 = 0.734 µM) and inhibits platelet aggregation induced by the TP receptor agonist I-BOP (; IC50 = 3.6 µM).³ It also selectively binds to leukotriene B4 (LTB4) receptor 2 (BLT2) over BLT1 at 5 µM in CHO cell membranes expressing the human receptors.⁴ It increases the proliferation of HT-29 colon cancer cells when used at a concentration of 1 µM.⁵ 12(R)-HETE inhibits the bovine corneal Na+/K+-ATPase in a concentration-dependent manner and decreases intraocular pressure in rabbits when administered topically at doses of 1, 10, or 50 µg/eye.^6,7 Intracerebroventricular administration of 12(R)-HETE (10 µg/animal) decreases LPS-induced pyresis in rats.⁸