Selective incorporation of 14C-arachidonic acid into the phospholipids of intact tissues and subsequent metabolism to 14C-prostaglandins.

A method is described for the efficient incorporation of radioactive arachidonic acid into the lipids of rabbit hearts and kidneys. Infusion of 14C-arachidonate through perfused tissues resulted in the quantitative removel of label from the media. Analysis of the lipids from tissues labeled by this procedure revealed that the majority of the 14C-arachidonate was incorporated into phospholipids. Essentially all of the radioactivity in phosphatidylcholine was found in the 2-position. Subsequent to the 14C-arachidonate infusion, stimulation of prostaglandin biosynthesis (e.g. by bradykinin) resulted in the release of radioactive prostaglandins. This suggests that the 14C-arachidonate is incorporated in a manner such that it is available for hormone-stimulated prostaglandin biosynthesis. The method described allows both qualitative and quantitative analysis of arachidonate metabolism in intact tissues and offers significant advantages over other presently used methods.