There is evidence that prostaglandins modulate renal hemodynamics in unilateral ureteral obstruction. We examined prostaglandin synthesis by glomeruli from rats with 24- and 72-h unilateral ureteral ligation. During prelabeling of the lipid pools with [14C]arachidonate glomeruli from the ligated kidney incorporated less 14C label than those from contralateral or normal control kidneys. However, the incorporation of [14C]arachidonate into phospholipids of glomeruli was proportionately higher in the ligated kidney. Incubation of the prelabeled glomeruli with either angiotensin II or bradykinin significantly increased release of labeled prostaglandins and turnover of [14C]arachidonate on the ligated side. Radioimmunoassay determinations showed that after 24-h ligation, glomeruli from both sides produced comparable amounts of PGF2 alpha, 6-keto-PGF1 alpha, TXB2, and PGE2. After 72 h, glomeruli from the ligated kidney produced more PGF2 alpha, 6-keto-PGF1 alpha, and TXB2 than the contralateral glomeruli. In contrast, PGE2 synthesis was higher in contralateral glomeruli. Neither angiotensin II nor bradykinin had a measurable effect on radioimmunoassayable prostaglandins. We conclude that unilateral ureteral ligation is associated with specific alterations of glomerular prostaglandin synthesis and phospholipid metabolism that are intrinsic to the glomerulus.