Biosynthesis of prostaglandins in the renal medulla of rabbit

IntroductionAn enzyme system present in the vesicular gland of sheep catalyzes the conversion of certain unsaturated fatty acids into prostaglandins [l-3] .The yields of PGE, and PGE,* from 8,11,14-eicosatrienoic acid and arachidonic acid, respectively, are very high (about 70%).Considerably lower yields of prostaglandins (2-5%) have been reported for homogenates of sheep intestine [2], guinea pig lung [4] and rat stomach [5] , whereas preparations of pig eye iris [6] and sheep thymus and sheep uterus [2] give very low yields (< 1%) of prostaglandins.The present paper reports the efficient conversion of arachidonic acid into prostaglandins by the renal medulla of rabbit. Materials and Methods5 6 8 9 11,12,14,15-octatritio-arachidonic acid , , , , was prepared by reduction of 5,8,11,14eicosatetraynoic acid (a generous gift of Dr. U.Gloor, Hoffman-La Roche dc Co., Basle, Switzerland) with tritium gas and Lindlar catalyst.Part of the product was diluted with unlabeled arachidonic acid and was purified by silicic acid chromatography.No impurities could be detected by gas-liquid radiochromatographic analysis of the methyl ester.The specific activity of this preparation was 44 pC/pmole.Crystalline PGE2 was a generous gift of Dr. J.