Pulmonary metabolism of prostacyclin (PGI2) in the rabbit.

Metabolism of prostacyclin, [9-³H]PGI₂, was examined in the isolated perfused rabbit lung and the post-microsomal supernate of rabbit lung homogenate. Two major metabolites of [9-³H]PGI₂ from the lung perfusate were separated by thin-layer chromatography and radiometric gas-chromatography. These two products were identified as 6 keto-PGF_1α and 6,15 diketo-13,14 dihydro PGF_1α by mass-spectrometry; they represented 65% and 14% of the total radioactivity. When [9-³H]PGI₂ was incubated with the lung homogenate in the presence of either NAD⁺ or NADP⁺, more than 36% and 25%, respectively, was converted to the 6,15 diketo-13,14 dihydro metabolite.