Abstract
1 . In each of six experiments, prostaglandins were identified in the renal venous blood of the rabbit. The concentrations in renal venous blood were up to 45 times higher than in aortic blood, suggesting that most of the prostaglandins originate from the kidney. 2 . Prostaglandins E2, F and a prostaglandin of the A, C or B series were estimated by biological assay after solvent partition and column or thin-layer chromatography. 3 . Prostaglandins E2 and F were identified conclusively by combined gas chromatography-mass spectrometry. 4 . Electrical stimulation of the renal nerve increased the output of prostaglandins. 5 . Indomethacin (10 mg/kg) injected intravenously, reduced the output of prostaglandins into renal venous blood and prevented the increase in output on renal nerve stimulation.