UROTHELIAL SYNTHESIS OF PROSTANOIDS IN THE OVINE URETER

The purpose of this study was to investigate the site of production (u rothelium/smooth muscle) and quantitative release of prostanoids in th e ureter. Quantitative analysis of prostacyclin (PGI(2)) was by its me tabolite, 6-keto PGF(1alpha), thromboxane (TXB2) and prostaglandin F-2 alpha. Synthesis by radiometry and radioimmunoassay was performed in v itro in sheep ureter specimens before and after removal of the inner e pithelial layer and after addition of indomethacin. The major prostano ids present in the ureter were PGI(2) and TXB2; PGI(2) was quantitativ ely the largest component. Removal of the thin inner epithelial layer (urothelium) reduced mostly PGI(2); addition of arachidonic acid signi ficantly augmented PGI(2) only in ureters with intact urothelium but d id not alter TXB2 levels. The main source of prostanoid synthesis (PGI (2)) of the ureter is to be found in the urothelium. The functional ro le of the prostanoids may be related to coordination of peristalsis.