Enzymatic formation of prostamide F2α from anandamide involves a newly identified intermediate metabolite, prostamide H2

Jinsong Ni,David F. Woodward,Wu Yang,Kah-Hiing John Ling,Diane D-S. Tang-Liu

doi:10.1194/jlr.m500374-jlr200

Abstract

Prostaglandin F2alpha 1-ethanolamide (prostamide F2alpha) is a potent ocular hypotensive agent in animals and represents a new class of fatty acid amide compounds. Accumulated evidence indicated that anandamide, an endogenous bioactive ligand for cannabinoid receptors, may serve as a common substrate to produce all prostamides, including prostamide F2alpha. After incubation of anandamide with cyclooxygenase 2 (COX-2), the reaction mixture was profiled by HPLC and an intermediate metabolite was discovered and characterized as a cyclic endoperoxide ethanolamide using HPLC-tandem mass spectrometry. Formation of prostamide F2alpha was also demonstrated when the intermediate metabolite was isolated and incubated with prostaglandin F synthase (PGF synthase). These results suggest that the biosynthesis of prostamide F2alpha proceeds in two consecutive steps: oxidation of anandamide to form an endoperoxide intermediate by COX-2, and reduction of the endoperoxide intermediate to form prostamide F2alpha by PGF synthase. This endoperoxide ethanolamide intermediate has been proposed as prostamide H2.

Highlights

Prostaglandin F2␣ 1-ethanolamide is a potent ocular hypotensive agent in animals and represents a new class of fatty acid amide compounds
To identify the potential biosynthetic pathway of prostamide F2␣, we conducted a series of metabolic studies of anandamide using recombinant human cyclooxygenase 2 (COX-2) and prostaglandin F synthase (PGF synthase) and analyzed the enzymatic metabolites using HPLCradiometric detection (HPLC-RAD) and HPLC tandem mass spectrometry (HPLC-MS/MS)
The results indicated that a prostamide congener of prostaglandin H2 serves as an intermediate metabolite of anandamide in prostamide F2␣ synthesis and demonstrated two consecutive enzymatic reactions in prostamide F2␣ formation

Summary

Introduction

Prostaglandin F2␣ 1-ethanolamide (prostamide F2␣) is a potent ocular hypotensive agent in animals and represents a new class of fatty acid amide compounds. Formation of prostamide F2␣ was demonstrated when the intermediate metabolite was isolated and incubated with prostaglandin F synthase (PGF synthase). These results suggest that the biosynthesis of prostamide F2␣ proceeds in two consecutive steps: oxidation of anandamide to form an endoperoxide intermediate by COX-2, and reduction of the endoperoxide intermediate to form prostamide F2␣ by PGF synthase. The results indicated that a prostamide congener of prostaglandin H2 serves as an intermediate metabolite of anandamide in prostamide F2␣ synthesis and demonstrated two consecutive enzymatic reactions in prostamide F2␣ formation

Methods

Results

Conclusion