Identification of metabolites from peroxisomal beta-oxidation of prostaglandins.

We have recently shown that isolated rat liver peroxisomes can chain-shorten prostaglandin F2 alpha and prostaglandin E2 to tetranor-metabolites. In the present report dinor-metabolites of these two prostaglandins were also identified, suggesting that the peroxisomal chain-shortening reaction of prostaglandins is a beta-oxidation reaction. Furthermore, an intermediate containing an extra double bond was isolated from incubates of prostaglandin F2 alpha with peroxisomes. This intermediate was tentatively assigned the structure 2,3-dehydroprostaglandin F2 alpha. Prostaglandin E1 and a major circulating prostaglandin F2 alpha metabolite were also metabolized to chain-shortened products by peroxisomes. The accumulation of the 2,3-dehydro-metabolite and the dinor-metabolites suggest that the peroxisomal beta-oxidation sequence is not tightly coupled, in contrast to mitochondrial fatty acid oxidation.