RENAL PROSTAGLANDIN EFFLUX INDUCED BY VASOPRESSIN, DDAVP AND ARACHIDONIC ACID: CONTRASTING PROFILE AND SITES OF RELEASE

SUMMARY 1. Prostaglandin (PG) efflux into ureteral (UE) and venous effluents (VE) of rabbit isolated perfused kidneys was determined by superfusion bioassay and radioimmunoassay (RIA), in response to injections of arginine‐vasopressin (AVP), the non‐pressor vasopressin analogue 1‐deamino‐8‐D‐arginine vasopressin (dDAVP) and arachidonic acid (AA). 2. dDAVP (10–1000 ng) failed to stimulate renal PG release, whereas AVP (10–100 ng) and AA (10–50 μg) caused a dose‐dependent release of PG. 3. AVP evoked PG release into both effluents with release into the VE greater than UE at high doses. In contrast, PG release by AA was almost exclusively into the VE. 4. Indomethacin (2.8 × 10‐6 mol/1) abolished AVP‐ and AA‐induced PG efflux in both effluents, and vasodepressor responses to AA. 5. PGE2 was the predominant PG released in response to AVP in both effluents whereas AA released primarily 6‐keto‐PGF1α. 6. The contrasting sites and profile of released PG suggest that exogenous AA and AVP stimulate the release of PG from different regions/cell types within the kidney.