The Effect of Arginine Vasopressin and Its Analogs on the Synthesis of Prostaglandin E2 by Rat Renal Medullary Interstitial Cells in Culture

Arginine vasopressin (AVP) stimulates renal prostaglandin (PG) production which is thought to inhibit vasopressins' antidiuretic action. Using rat renal medullary cells in culture (RMIC), we compared the ability of the following peptides which possess different biological activities to stimulate prostaglandin biosynthesis: AVP (high antidiuretic and pressor activities); 1-desamino-8-D-arginine vasopressin (a synthetic peptide with high antidiuretic and no pressor activity); and oxytocin (intermediate pressor, low antidiuretic activity). Radiometric thin-layer chromatography of supernatant media from cells incubated with octatritiated or [14C]arachidonic acid revealed only one radiolabeled peak which co-migrated with PGE2. Radioimmunoassay confirmed that PGE2 was the only prostaglandin synthesized by RMIC. Incubation of cells with AVP (1 nM to 3 microM) increased PGE2 synthesis measured by radioimmunoassay in a concentration-dependent fashion up to 2 1/2-fold over control; 1-desamino-8-D-arginine did not increase PGE2 synthesis. Oxytocin stimulated PGE2 synthesis, but was less potent than AVP. Preincubation of RMIC with [1-(beta-mercapto-beta, beta-cyclopentamethylene propionic acid)-4-valine, 8-D-arginine]vasopressin, a synthetic nonpressor, nonantidiuretic antagonists of AVP's pressor activity, completely blocked the ability of AVP to stimulate PGE2 synthesis. We conclude that the ability of AVP to stimulate PGE2 synthesis in RMIC is related to its pressor, not its antidiuretic, activity.