The identification of prostaglandins E2, F2α and A2 from rabbit kidney medulla

Abstract

Rabbit kidney medulla (10kg.) was homogenized in 5mm-disodium hydrogen phosphate and deproteinized with ethanol, and the concentrated supernatant solution was extracted at pH8 with light petroleum and at pH2 with chloroform. The acidic lipids present in the chloroform phase were separated on silicic acid columns into three biologically active fractions. The first fraction contained only vasodepressor activity; the second fraction contained both vasodepressor and non-vascular-smooth-muscle-stimulating activity; the third fraction contained both vasopressor and non-vascular-smooth-muscle-stimulating activity. Purification of each fraction by reversed-phase partition and thick-layer chromatography yielded three pure acids. Thin-layer chromatographic, spectroscopic and mass-spectral analysis of the acids and their methyl esters established their structures as prostaglandins E2, F2α and A2. Evidence is presented demonstrating that part or all of the prostaglandin A2 is formed during the isolation procedures from endogenous prostaglandin E2.