Subsequent to the formation of PGH₂, the cytochrome P450 activities thromboxane synthase (CYP5A1, TBXAS1, P24557 , EC 5.3.99.5) and prostacyclin synthase (CYP8A1, PTGIS, Q16647, EC 5.3.99.4) generate thromboxane A₂ and prostacyclin (PGI₂), respectively. Additionally, multiple enzyme activities are able to generate prostaglandin E₂ (PGE₂), prostaglandin D₂ (PGD₂) and prostaglandin F_2α (PGF_2α). PGD₂ can be metabolised to 9α,11β-prostacyclin F_2α through the multifunctional enzyme activity of AKR1C3. PGE₂ can be metabolised to 9α,11β-prostaglandin F_2α through the 9-ketoreductase activity of CBR1. Conversion of the 15-hydroxyecosanoids, including prostaglandins, lipoxins and leukotrienes to their keto derivatives by the NAD-dependent enzyme HPGD leads to a reduction in their biological activity.

YS121 has been reported to inhibit mPGES1 and 5-LOX with a pIC₅₀ value of 5.5 [11].

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