2.2. Prostaglandin E Metabolite (PGEM) Assay

Plasma PGE₂ levels were quantified using a Prostaglandin E Metabolite (PGEM) enzyme-linked immunosorbent assay (ELISA) kit (Cayman Chemical Company, Ann Arbor, MI, USA, cat. No. 514531), which converts 13,14-dihydro-15-keto PGE₂ and 13,14-dihydro-15-keto PGE₂ to a single, stable derivative. The assay was conducted according to the manufacturer’s protocol, as previously described [21]. Briefly, after samples were purified by acetone precipitation, they were dried under a nitrogen stream. Samples were then resuspended in ELISA buffer and derivatized overnight. A 1:5 sample dilution was assayed in duplicate.