(±)18-HETE is the racemic version of a cytochrome P450 (CYP450) metabolite of arachidonic acid. When formed by the CYP2E1 isoform, 18-HETE is comprised 100% of the (R) isomer. 18(R)-HETE dose-dependently stimulates vasodilation of the rabbit kidney, whereas 18(S)-HETE does not affect perfusion pressure. 18-HETE has negligible effects on ATPase activity. 18(R)-HETE at 1 μM completely blocks 20-HETE-induced vasoconstriction of renal arterioles.