Urinary prostaglandins. Identification and origin.

Human urine was analyzed by mass spectrometry for the presence of prostaglandins. Prostaglandin E2 and F2alpha were detected in urine from females by selected ion monitoring of the prostaglandin E2-methylester-methoxime bis-acetate and the prostaglandin F2alpha-methyl ester-Tris-trimethylsilylether derivative. Additional evidence for the presence of prostaglandin F2alpha was obtained by isolating from female urine an amount of this prostaglandin sufficient to yield a complete mass spectrum. The methods utilized permitted quantitative analysis. The origin of urinary prostaglandin was determined by stimulating renal prostaglandin synthesis by arachidonic acid or angiotensin infusion. Arachidonic acid, the precursor of prostaglandin E2, when infused into one renal artery of a dog led to a significant increase in the excretion rate of this prostaglandin. Similarly, infusion of angiotensin II amide led to a significantly increased ipsilateral excretion rate of prostaglandin E2 and F2a in spite of a simultaneous decrease in the creatinine clearance. In man, i.v. infusion of angiotensin also led to an increased urinary eliminiation of prostaglandin E. These results show that urinary prostaglandins may originate from the kidney, indicating that renally synthesized prostaglandins diffuse or are excreted into the tubule. Thus, urinary prostaglandins are a reflection of renal prostaglandin synthesis and have potential as a tool to delineate renal prostaglandin physiology and pathology.